# Need help with my custom frame



## kpw2011 (May 7, 2012)

Hi, i am ordering a custom hard-tail frame from Marino. I am discovering it is harder to spec the geo than i thought. i have attached a diagram , it is not my design but it is looking like its what i want with a couple of adjustments . i need a longer axle to crown to fit a 180mm lyric. I am building it 275 but want to be able to run 29er later. I am wondering about the -50 BB drop. mostly i pedal up logging rds, they are smooth enough i think, but never had a -50mm drop before. if i want to make it 29er eventually perhaps i should keep the -50mm BB. i assume i should shorten the head tube to perhaps 130mm? as i will be running a longer axle to crown at around 570mm. I like the HA of 61.5, im aiming for a very DH type of hardtail. But with some ability to pedal up. so i just need gears and a longer dropper. I cannot really tell if it will fit, the numbers look about the same as my previous bikes, a large dartmoore hornet, a M/L chromag rootdown. My full sus transition patrol size large is bigger reach numbers wise but im told i have to size down those numbers to fit a hard tail. 
Any thoughts? am i nuts?

cheers kev


----------



## scottzg (Sep 27, 2006)

I have an XL '16 patrol, and i would be fine with importing the rider fit to a hardtail design. It wouldn't translate perfectly, of course.

I'm fine with a 50mm bb drop on a long travel 650b hardtail, but i'm more tolerant of low bb height than most. I think it's stupid to design for both 650 and 29, though.

If in doubt, go with the shorter head tube. It's much easier to install high-rise bars than it is to track down a flatforce stem or such. 130mm isn't excessively short.

I would struggle to keep my weight forward enough on the bike you propose. I need my 'leaning back on the handlebars' position to not completely unweight the front wheel. My form isn't perfect...

The design seems unbalanced. Massively stable front end, with suuuper short and rigid rear end. The situations where both those things play nice together is very small, at least for my skill set.



With geo, you should see what people say, and then ignore it and go with your gut.


----------



## cassieno (Apr 28, 2011)

Have you tried contacting Marino for advise?


----------



## kpw2011 (May 7, 2012)

cassieno said:


> Have you tried contacting Marino for advise?


Hi. Not yet but I will. 
Cheers


----------



## pvd (Jan 4, 2006)

1. The head angle is far too slack. Don't copy Sick, those are terrible bikes. 65 degrees is about as slack as I go. Stantion bind is real.
2. It's quite low for use with SPD. Stupid low if with flats. A bike for flats will be about an inch higher than SPD.
3. The cockpit and fit seem to not been done well. Take that seriously for the bike to fit. This is really important.
4. Draw the bike at 30% sag.
5. A performance bike will have 29" wheels. Why are these so small?


----------



## kpw2011 (May 7, 2012)

scottzg said:


> I have an XL '16 patrol, and i would be fine with importing the rider fit to a hardtail design. It wouldn't translate perfectly, of course.
> 
> I'm fine with a 50mm bb drop on a long travel 650b hardtail, but i'm more tolerant of low bb height than most. I think it's stupid to design for both 650 and 29, though.
> 
> ...


Hi, i like the advise, i will not ignore it. I take your point re 275 and 29er. its not a good idea, but i didnt get where i am today by being smart. I agree, i will make it 275 because i have a 275 build kit available.

Shorter head tube and adjust with riser bars is a good idea, Originally i had specified a 110mm so i will go back to that.

Why would you struggle to keep your weight forward? is it just because its long travel and slack like a DH bike. I am copying a BRT Belter with a modification of a longer travel fork. I have ridden many 64 deg HA 180mm hardtails and they have been good. This design of 61.5 is before sag and should settle at 63 HA just like a DH bike.

The designs purpose is just to be good at DH and ok ish at up hill pedals, im ok with walking up the steeper climbs too. But i can climb my DH bike up all but the steepest ups. I will probably lengthen the chain stays to improve climbing.


----------



## kpw2011 (May 7, 2012)

pvd said:


> 1. The head angle is far too slack. Don't copy Sick, those are terrible bikes. 65 degrees is about as slack as I go. Stantion bind is real.
> 2. It's quite low for use with SPD. Stupid low if with flats. A bike for flats will be about an inch higher than SPD.
> 3. The cockpit and fit seem to not been done well. Take that seriously for the bike to fit. This is really important.
> 4. Draw the bike at 30% sag.
> 5. A performance bike will have 29" wheels. Why are these so small?


Hi, i am concerned about the HA, but BTR Belter uses 61.5, i have talked with people using them at 61.5. and they seem happy, good dh and surprising good climbs considering. after sag it will be 63 HA. im not looking for a well balance up/down bike. I want a DH focused Hardtail that i can pedal up even if it is a little flip flopy around on the steeper climbs.

great point about the clip-less and flat pedals. I use only flats. But -50 BB is a lot. i am concerned about that. It is 20mm lower than im used to.

'' The cockpit and fit seem to not been done well. Take that seriously for the bike to fit. This is really important.'' .....can you explain a little more? I am very concerned i will build a bike and its too long, or low or too tall front end. Im typically a size large but only just, i need a small size large. I have used reach and seat tube angles of common hardtail brands i trust and have ridden, chromag, transition, dartmoor etc. they all seem to have a reach of 450mm reach, 75 deg seat tube approx. The stack is high because of the 180mm fork im using.

i would like 29 wheels, i just have a good 275 wheelset and lyric fork kicking around so im going 275. may be that is short sighted of me. i have never really ridden a 29er, but since moving from a 26 DH to 275 DH bikes i hit the back wheel so hard it bucks me. had some close calls almost over the bars a few times. So a 29er must have less rear clearance and be worse! for me that is . 
cheers mate.


----------



## pvd (Jan 4, 2006)

Looking at that bike, it's garbage. I think you are making the assumption that just because something is sold then it is good. The BTR are fairly low end bikes and really aren't worth referring to.

This is a modern trail bike:

I don't make bicycles. I make weapons systems. | Peter Verdone Designs










It's far more capable than what you are referring to and certainly a faster bike. It has a steep enough head tube and slack enough seat tube for real rides but can descend better than any bike you've ever ridden. That's what good design is. We don't choose to make a $hit bike that can only go down a hill slow. We design a bike that can go up and down fast.










Notice all the dimentioning from the saddle to the ends of the handlebars? The specificity of the saddle location? The front center and specific bar placement? That's what you need to do. Designing a bike is different than posting on PinkBike. You need to focus on the real details rather than the ones people talk about.


----------



## kpw2011 (May 7, 2012)

pvd said:


> Looking at that bike, it's garbage. I think you are making the assumption that just because something is sold then it is good. The BTR are fairly low end bikes and really aren't worth referring to.
> 
> This is a modern trail bike:
> 
> ...


Thats a lot of good information. Im beginning to realize i know nothing of bike geo. no more than the average joe at least. I need to digest it and reconsider. Im building a custom frame because i have not found an off the shelf frame i like. But i am fussy. Ive ridden many bikes, i own 6 rite now. 170mm and 64deg HA is the shortest travel and steepest HA i have. in general my thought process was i want it to DH very well, up hill i can compromise on. I want it to fit, i have very short inseam. ...size small legs but im 5' 10''tall and generally ride a large bike but find them a little long and tall. i want it to look like a dirt jumper with the top tube in line with the chain stays. Im my experience long travel , slack HA and long wheel base works best for me. So now im totally confused, i had a lot of momentum heading towards the slack HA BTR Belter style of bike. Not sure what to do. and it isnt just your post, ive heard the same feedback many times before so its making me rethink. perhaps I need something like the chromag Doc Hawk but customized to fit my body.


----------



## kpw2011 (May 7, 2012)

so this was my original design with marino but i think its too big for me. the 475mm reach is from my large patrol and i find it a little too long and have to run narrower bars to compensate. i wonder what you think of this.? its a 29er spec . but as i only have a 275 build kit i was going to build it 275 initially. ! perhaps a steeper seat tube angle and longer chain stays is all it needs? its a little closer to a doc hawk i think.
Any feedback is much appreciated. crap or not? DH is the focus.


----------



## cassieno (Apr 28, 2011)

The doc hawk was designed for literally one person on one type of terrian. Steep rock rolls. If that's how you ride it may work for you.

I am a little confused why you have 6 long travel bikes with slack HA and you are unhappy with them so just want to go slacker....on a hardtail? 

The Doc hawk style of bike is a silly extreme of "modern geometry"

However for $250 just buy whatever you want and if you don't like it understand what it is you don't like about it and go from them there. 

Might as well buy like 4 frames with distinct differences and see what you like the most. 

Just be ready to keep spending as you try and figure out your "perfect"


----------



## *OneSpeed* (Oct 18, 2013)

Not all of these apply but some of the more aggressive options may be a useful reference.

(I agree your initial take on geo is way off, for me)

Stanton, Chromag, GG, Pipedream, Orange, Commencal, etc all make aggressive hardtails with a variety of geometries.

Some reading...

https://enduro-mtb.com/en/best-hardcore-hardtail/

https://www.redbull.com/gb-en/10-best-trail-hardtail-mountain-bikes

https://www.singletracks.com/blog/mtb-gear/10-hardcore-hardtails-mountain-bikes-get/

https://www.pinkbike.com/news/4-hardcore-hardtails-core-bike-2019.html


----------



## pvd (Jan 4, 2006)

1. 29er wheels are 750mm diameter in most designs.
2. The seat tube is way too steep. The effective seat angle is even steeper (not shown) as dropper posts have 0mm offset.
3. Draw the bike with saddle at proper pedaling height. Draw in a 210mm dropper post. If this fits, it's fine for DH.
4. You've done no work on fit. 'reach' is not a fit parameter. Look at the drawing I shared.
5. The head tube angle is still way too slack. Certainly too slack for using a Pike. You will need a far heavier fork for this. Probably, a Lyric.
6. If this is for DH, Why are you designing around such a short fork. Sure, it's a 180mm 27.5" fork but that's only 160mm if you are using a 29" fork. Nobody is using 27.5" front wheels any more. Designing around that is silly.
7. The 639mm, 637mm, 475mm, are useless design dimensions.
8. 415mm is a very challenging build for 29" wheeled chainstays. You'll need a yoke for that. You may want to make some space there to keep your costs down.


----------



## scottzg (Sep 27, 2006)

kpw2011 said:


> Thats a lot of good information. Im beginning to realize i know nothing of bike geo. no more than the average joe at least. I need to digest it and reconsider. Im building a custom frame because i have not found an off the shelf frame i like. But i am fussy. Ive ridden many bikes, i own 6 rite now. 170mm and 64deg HA is the shortest travel and steepest HA i have. in general my thought process was i want it to DH very well, up hill i can compromise on. I want it to fit, i have very short inseam. ...size small legs but im 5' 10''tall and generally ride a large bike but find them a little long and tall. i want it to look like a dirt jumper with the top tube in line with the chain stays. Im my experience long travel , slack HA and long wheel base works best for me. So now im totally confused, i had a lot of momentum heading towards the slack HA BTR Belter style of bike. Not sure what to do. and it isnt just your post, ive heard the same feedback many times before so its making me rethink. perhaps I need something like the chromag Doc Hawk but customized to fit my body.


How about something like this?








The grey bike is better than the blue one but they both look like a handful.


----------



## kpw2011 (May 7, 2012)

cassieno said:


> The doc hawk was designed for literally one person on one type of terrian. Steep rock rolls. If that's how you ride it may work for you.
> 
> I am a little confused why you have 6 long travel bikes with slack HA and you are unhappy with them so just want to go slacker....on a hardtail?
> 
> ...


I love steep rock rolls and it is my preferred trail. steep rock rolls, or so steep and loose dirt shoots that you cannot even walk down it. Going up hill , it is nice to pedal but i dont care too much if i push up. 
I love all of my bikes, everyone is perfect except the hardtail, a 2017 chromag rootdown, 180mm lyric. It feels unstable on really steep DH, it feels like im going over the bars, or about too. so im looking for a DH hardtail. I dont want to order 4 frames, but if i dont get the geo rite then i could end up with 4 wrong ones! and i dont think i know enough about fit to get it rite. so copying geos from bikes ive had in the past is what ive done. but may be created just a mess. ?


----------



## kpw2011 (May 7, 2012)

scottzg said:


> How about something like this?
> View attachment 1277427
> 
> 
> The grey bike is better than the blue one but they both look like a handful.


That looks great, thank you. But why is it better than the Grey one? educate me?

cheers kev


----------



## scottzg (Sep 27, 2006)

kpw2011 said:


> That looks great, thank you. But why is it better than the Grey one? educate me?
> 
> cheers kev


ummm... it may not be as good for fall-line trails. Shorter front-center.

My design has you body more forward over the front wheel when you're in the attack position, but still has a long wheelbase. Should be more intuitive to ride. Adjustable dropouts give you more flexibility in setting up the cockpit or to tweak weight distribution.

Anything that's been posted is a long way away from an overforked rootdown.


----------



## Cord (Dec 10, 2006)

I think any head angle under 62° just won’t work. I did quite a bit of work testing DH bikes (all be it a few years ago, and bushings have maybe???? moved on) We found that anything under 63° created a lot of bind, what you gained in stability (actually quite little after 64°) you lost due to your forks effectively not working on small to mid size hits. As for those ridiculous short chainstays, they are at odds with your slow stable front end. I don’t really understand what this bike is trying to achieve.


----------



## kpw2011 (May 7, 2012)

Cord said:


> I think any head angle under 62° just won't work. I did quite a bit of work testing DH bikes (all be it a few years ago, and bushings have maybe???? moved on) We found that anything under 63° created a lot of bind, what you gained in stability (actually quite little after 64°) you lost due to your forks effectively not working on small to mid size hits. As for those ridiculous short chainstays, they are at odds with your slow stable front end. I don't really understand what this bike is trying to achieve.


That makes some sense to me. never really thought you could go too slack but it does make sense that the forks will not work as well, perhaps down to the angle of bump force applied. So 63deg is the new slack HA for me, and a longer chain stay.

I have a question. My assumption is the HA of 61.5 in my diagram is before sag, i read an article on BTR website that stated it will sag to 63 under load which makes sense. As the rear of a HT does not sag. so static HA 61.5, under sag its 63 like a DH bike. that is why i bought into the 61.5 HA . i want DH slack. Does that make any sense? is that nonsense? 
cheers
i appreciate everybody's help.


----------



## Cord (Dec 10, 2006)

I’d have to break out the calculator to check, but I’d be surprised if 35mm??? of sag changed it by 1.5°, it will certainly have an effect tho. I think however that you’ll find it very hard to repeatable set sag on a 61.5° head angle, the time you are applying the lightest compression force to the suspension, is exactly when it’s most likely to bind. 

When I was involved with testing DH bikes for World Cup riders at one point we attached a go-pro looking back at the side view of the forks to better help us understand the strange data acquisition results we were getting. It’s amazing how much a set of triple clamp forks can flex forwards from a flat landing. It gave us a major shift in thinking with regards to “slacker is better”


----------



## scottzg (Sep 27, 2006)

kpw2011 said:


> = i want DH slack. Does that make any sense? is that nonsense?


it sounds like you're confounding front-center and head angle.

It can be helpful to determine how much front-center you want and how big a cockpit you need (like, just import the saddle clamp-handlebar clamp distance and drop from your patrol). Then adjust reach, chainstays, and head/seat angles to fit those dimensions.

You should model your chromag as accurately as possible so you can see what you're coming from.

I don't understand how Marino makes a profit on those frames. Materials + shipping = his asking price.


----------



## Drew Diller (Jan 4, 2010)

scottzg said:


> I don't understand how Marino makes a profit on those frames. Materials + shipping = his asking price.


Wowza, at first I was thinking "Oh Scott don't be just another dude with too much money on his hands" so I went to go check the prices myself - waitadangminute - WHAT THE HECK?! Those are like the prices of a good stock Taiwanese mass produced frame. How does he get by? Extreme volume? *boggle*


----------



## scottzg (Sep 27, 2006)

Drew Diller said:


> Wowza, at first I was thinking "Oh Scott don't be just another dude with too much money on his hands"


I dream of the day that i'm so wealthy i have no idea what things cost.

Until then, speculating about how Marino is able to turn a profit at those prices is free. Even if he's figured out how to run so lean... it's so far under market value it doesn't make sense. I don't understand his business model.

My commuter is an old on-one inbred frame i bought new for 150$. I've looked in to financing a production run of its modern equivalent. I can't figure out how to do the business-side work, run/mitigate the financial risk, and still pay myself minimum wage for marketing and shipping. I have a ton of respect for people who can produce a niche product at market rate.


----------



## kpw2011 (May 7, 2012)

scottzg said:


> it sounds like you're confounding front-center and head angle.
> 
> It can be helpful to determine how much front-center you want and how big a cockpit you need (like, just import the saddle clamp-handlebar clamp distance and drop from your patrol). Then adjust reach, chainstays, and head/seat angles to fit those dimensions.
> 
> ...


That's great advice, ive been reading and learning about this subject, thanks to everybody here for helping me. I have some homework to do. I think I'm going to bite the bullet and pay the deposit today to marino. They have been kind enough to produce the first diagram for me free. But I don't want to ask for modifications until ive paid and/or until I understand what I want.


----------



## kpw2011 (May 7, 2012)

Cord said:


> I'd have to break out the calculator to check, but I'd be surprised if 35mm??? of sag changed it by 1.5°, it will certainly have an effect tho. I think however that you'll find it very hard to repeatable set sag on a 61.5° head angle, the time you are applying the lightest compression force to the suspension, is exactly when it's most likely to bind.
> 
> When I was involved with testing DH bikes for World Cup riders at one point we attached a go-pro looking back at the side view of the forks to better help us understand the strange data acquisition results we were getting. It's amazing how much a set of triple clamp forks can flex forwards from a flat landing. It gave us a major shift in thinking with regards to "slacker is better"


Oh now I get it....the suspension bushings bind up due to angle of applied force. yes that makes perfect sense. Thank you for bearing with me!.


----------



## kpw2011 (May 7, 2012)

hi everybody. here is my latest attempt. it does go against some of your advice so bear with me or try again to make me see sense. My main concern is the fit of the bike.

I'm still learning and STILL in the process of designing. I still want it to be 275 wheels. and I still really want to try 61.5 HA. I do believe the feedback on the forum that the front suspension will not be so soft but I'm so curious about this HA that I want to try it. I ride trails with really steep rock slabs, almost vertical. I have never taken a hard tail down some of the bigger slabs because ive never had a hard tail that I can control in such a situation. so I'm designing it to handle the most difficult 5% of my fav trails, because if I cannot ride those features then I do not ride that trail at all. 
I have been deciding on the fit. I just do not know enough about geo to be really sure so I looked at many hardtails ive had and or would purchase and chose reach and seat angles from those. My size large transition patrol reach of 475 is to big for me. so I'm going for 450mm reach and I lengthen the chain stays to 420mm and slackened the seat tube to 74. again, I really am uneducated so its a lot of guess work. I am wondering if I should lengthen the chain stays to 425mm and slacken the set tube to 73 perhaps? I don't know. Let me know what you think.


----------



## *OneSpeed* (Oct 18, 2013)

So build it the way you want and come back here and tell us all how awesome it isn't. 

I'm out. Good luck.


----------



## scottzg (Sep 27, 2006)

Here's your 2017 m/l rootdown for comparison's sake.


----------



## kpw2011 (May 7, 2012)

scottzg said:


> Here's your 2017 m/l rootdown for comparison's sake.
> 
> View attachment 1280165


Thank you. My root down fits well in length but is too tall in stand-over and seat tube is WAY to tall. Its also unstable for me on steep tec or high speed steep rock slabs and only suitable for general trail riding. At least for my skillset. So this is why i am trying to improve on the rootdown but stick with steel at a reasonable price. Im happy for any feed back, i think i improved the forward position. more weight forward, lengthening the chain stays help with stability. The HA is crazy slack, i can only go by others who have ridden such HA and liked it. it doesn't mean i will though. maybe i will end up putting a slackening headset in backwards !!! but im not wanting a well rounded do it all bike. Its 90% DH intended. 
just thought i would post to see the reactions. 
cheers
kev


----------



## Cord (Dec 10, 2006)

In your own words, you want it to work for the 5% of trail that excites you, why are you concerned about 1º of seat tube angle, this will have no effect at all when you are stood up in attack mode? Besides, you could basically get the same adjustment by moving seat on its rails, or layback/straight post. 

I'm not really sure what advice to offer, maybe just build it. At the end of the day, if it's crap, hang it up in the rafters and try something different!!!


----------



## Cgocal (May 12, 2021)

kpw2011 said:


> hi everybody. here is my latest attempt. it does go against some of your advice so bear with me or try again to make me see sense. My main concern is the fit of the bike.
> 
> I'm still learning and STILL in the process of designing. I still want it to be 275 wheels. and I still really want to try 61.5 HA. I do believe the feedback on the forum that the front suspension will not be so soft but I'm so curious about this HA that I want to try it. I ride trails with really steep rock slabs, almost vertical. I have never taken a hard tail down some of the bigger slabs because ive never had a hard tail that I can control in such a situation. so I'm designing it to handle the most difficult 5% of my fav trails, because if I cannot ride those features then I do not ride that trail at all.
> I have been deciding on the fit. I just do not know enough about geo to be really sure so I looked at many hardtails ive had and or would purchase and chose reach and seat angles from those. My size large transition patrol reach of 475 is to big for me. so I'm going for 450mm reach and I lengthen the chain stays to 420mm and slackened the seat tube to 74. again, I really am uneducated so its a lot of guess work. I am wondering if I should lengthen the chain stays to 425mm and slacken the set tube to 73 perhaps? I don't know. Let me know what you think.
> View attachment 1280153


Not sure if you got the bike in the end but i do have to say geometry is very personal! I am gonna order from marino soon. For reference my full sus geo is 520mm reach but want longer, 453cs, 77sta (want steeper), 62.5 HA. for my hardtail I have come up with this


----------

