# Head tube angle for kid



## TheSandwichProtector (Jul 8, 2020)

I'm looking at building a bike for my 11yr old starting with a HT Chinese carbon frame. Something like this:

262.02US $ 41% OFF|THRUST Carbon Frame 29er 15 17 19 Carbon mtb Frame 29 er BSA BB30 Bike Bicycle Frame Max Load 250kg 2 Year Warranty 18 Colors|frame 29 er|carbon frame 29ermtb frame 29 - AliExpress

However, I'd like to get something a little more slack. All the HT frames I can find seem to have a head tube angle of 69.5 or 70 deg. I guess my question is how much can I change that through fork, and other parts? I've seen a few companies like wolftooth put out an adjustable headset. If so is that the right move? Or should I just take the 70deg angle, build the bike and not worry about it? I was hoping to get to 67-68 deg if possible.
My daughter is 5ft, 65lbs and fairly timid on trail. I was thinking Carbon XS frame, 27.5 wheels and 120mm fork. I'm really nervous about buying all the parts and building the bike since I've never done anything like that before, but I'm willing to try.
Any help or advice would be greatly appreciated!


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## Tommy E (Oct 30, 2019)

Not really answering your questions, but my daughter started riding about your daughter's age although I think my daughter was a little shorter than 5 feet tall at the time. The frame you linked appears to be too big for your daughter at her current height. The dimension specs on that bike are all over the place and do not appear to be accurate. The small 15 shows the seat tube to be 400 mm which is 15.78 inches and the reach to be 580 mm which is way out there for a small xc style bike, lol. My daughter who is now 5 foot 5 inches tall rides a 27.5 medium chameleon frame that I built up and she loves it. My daughters biggest issue back then was wanting her dropper to go low enough that she could stand flat footed while still being seated which I had to find a bike with a very short seat tube length in order to accomplish. I guess it gave her some sort of peace of mind by thinking if she could touch the ground if things went south then she'd be ok, lol. Some brand name frames aren't too much more than the price of the frame you linked. Good luck with your venture.


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## TheSandwichProtector (Jul 8, 2020)

Thanks for the response Tommy. I was using the previous link more as an idea. Here's one with better numbers...









228.8US $ 45% OFF|Carbon bike frame new geometry carbon bicycle frame T1000 148mm and 142mm thru axle carbon racing bike frame 29er MTB|Bicycle| - AliExpress

I've been looking at all the brand name stuff, but they're either too heavy or too $. I'd like to stay around $1500 and as far under 30lbs as I can get. We rented her an xs full sus when we were in Bentonville for a trip and she hated pedaling it up hill. I think it was around 33lbs. My thought was I can build her a super light weight HT while adding a dropper and some nicer brakes and fork then what I'd get with a heavier budget HT like a Rockhopper or something.


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## FrankS29 (Oct 23, 2019)

My daughter has been riding a medium Salsa Timberjack (last gen, not current) frame since she has been 5' tall.

I could not find a new bike to buy her, so I built up the frame I had on hand to test how it would be, she fit it great.

Put on a 40mm stem, cut some bars to about 680mm, put 165mm cranks on it with 27.5+ wheels and a Whiskey No.9 boost carbon fork.

I have several spacers above the stem so that as she grows, I can raise the stem up, put wider bars on, longer stem...

She loves it.


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## TheSandwichProtector (Jul 8, 2020)

Thanks Frank! That's helpful to know you were able to get her on a medium, size down the parts and make it work well. How much does the bike weigh? I was originally looking at the Timberjack, Specialized Fuse, and Fezzari Wasatch Peak. All of the sub 2k models come in around 33lbs. I was hoping to do better if I could, which lead me to the Chinese carbon frame option.


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## rton20s (Aug 27, 2010)

Bad geometry is bad geometry. I'd take the weight penalty any day, unless you are thinking straight XC or bike path rides. The same holds true for my kids' bikes. Within reason. 

Bikes can be tough to get right now, but I would probably just keep an eye out for a decent quality complete hardtail within your budget. Don't just limit yourself to new, either. If you're patient, you can still find decent deals on site like pinkbike and local classified groups.


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## lixxfe (Apr 19, 2012)

Putting a longer fork on the bike to slacken the head tube angle will increase the bottom bracket height and slacken the seat tube angle. Roughly, you need a 20mm longer fork to decrease HT angle by 1 degree. Seat tube angle will slacken by the same amount. Bottom bracket height will increase by about 8mm (40% of 20mm, ratio of chainstay length to wheelbase). 

To compensate for the slacker seat tube angle, you can use a 9point8 fall-line-R dropper with 'forehead' option. You will need to check the max drop you can use because the seat tube length is on the long side. The nice thing about the 9point8 post is that you can shim down the stroke. 

To compensate for the higher bb, your could buy a 29 frame, run 27.5 wheels, and use a short crank, which would probably be better for your daughter anyway. (My son, at 4'8" runs 140mm cranks. I'm almost 5'10" and running 165mm). The wheel switch alone would drop the bb by about 25mm. Most frame are designed around 175mm cranks so you could probably run 150mm cranks with no issues.

Depending on headtube standard the frame uses, you could get a -1.5degree headset from Works Components or Cane Creek. Actual angle will be a bit less because the raked out fork will drop the head tube which will steepen the head tube angle. The advantage here is that the seat tube angle will actually sharpen up a bit and the bottom bracket height will drop a bit. (To determine what a 'bit' equals, you would have to do some trig with the actual frame numbers, or find one of those bike geometry websites that are supposed to be out there.) I would still strongly suggest you consider a 29er frame with 27.5 wheels to drop the bottom bracket, and run height-appropriate crank length. Lower BB height will lower stand over and provide confidence boost. 

Anyway, a fun rabbit hole to go down!


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## rton20s (Aug 27, 2010)

TheSandwichProtector said:


> Thanks Frank! That's helpful to know you were able to get her on a medium, size down the parts and make it work well. How much does the bike weigh? I was originally looking at the Timberjack, Specialized Fuse, and Fezzari Wasatch Peak. All of the sub 2k models come in around 33lbs. I was hoping to do better if I could, which lead me to the Chinese carbon frame option.


Keep in mind that much of the weight of those sub-$2k bikes is from the components as much as the frame. You'll run into the same challenge trying to build up a bike from parts within your $1500 budget. Unless you have a lot of lightweight parts laying around? I'd bet to stay in budget your bike build will still be 31+ lbs with one of the Alibaba carbon frames.


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## lixxfe (Apr 19, 2012)

rton20s said:


> Keep in mind that much of the weight of those sub-$2k bikes is from the components as much as the frame. You'll run into the same challenge trying to build up a bike from parts within your $1500 budget. Unless you have a lot of lightweight parts laying around? I'd bet to stay in budget your bike build will still be 31+ lbs with one of the Alibaba carbon frames.


So true! It's amusing to hear folks complain about how heavy kids bikes are, and, in the same breath, how expensive they are! Kids bikes use adult bike components. Getting them lighter costs the same as getting an adult bike lighter. The weight difference from shorter bars, smaller wheels, etc. is negligible.


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## abeckstead (Feb 29, 2012)

Don't over think it Dad... just let her ride, learn and have FUN!. I started my kids on tanky hardtails (spesh hotrocks, dirt jumpers etc.) at the ages of 5 & 7. They're now 14 & 17 and pretty good riders and doing high school mtb racing. Honestly the best bike upgrade I can't recommend enough is to put a dropper post on the bike. Makes a world of difference, especially for a timid rider.


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## TheSandwichProtector (Jul 8, 2020)

Thanks so much for all the responses and advice everyone! I guess I'll go back to searching for one of the budget friendly HTs we've been discussing above. Anyone have any experience with the Fuse or Fezzari Wasatch Peak?


abeckstead said:


> Don't over think it Dad... just let her ride, learn and have FUN!. I started my kids on tanky hardtails (spesh hotrocks, dirt jumpers etc.) at the ages of 5 & 7. They're now 14 & 17 and pretty good riders and doing high school mtb racing. Honestly the best bike upgrade I can't recommend enough is to put a dropper post on the bike. Makes a world of difference, especially for a timid rider.


Haha, but I'm a Dad, it's what I do!


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## FrankS29 (Oct 23, 2019)

TheSandwichProtector said:


> Thanks Frank! That's helpful to know you were able to get her on a medium, size down the parts and make it work well. How much does the bike weigh? I was originally looking at the Timberjack, Specialized Fuse, and Fezzari Wasatch Peak. All of the sub 2k models come in around 33lbs. I was hoping to do better if I could, which lead me to the Chinese carbon frame option.


Honestly, I haven't put it on a scale. If I had to guess, it's in the mid 20's.

The carbon fork trims a ton of weight. All the bikes you mentioned come with pretty hefty forks and fairly heavy entry level parts spec.

I built hers with a mix of XT/SLX 11 speed parts, carbon seat post (cut so that I could slam it at first), Stans Major wheelset&#8230;


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## ilmfat (Mar 10, 2007)

They notice draggy tires more than weight.

12" 29er. 4'6". Not many 12" 9ers these days.









Her older sister a season earlier. 4'8". Had her ride an xs B+ and a small 29er. She chose the small.


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## Zguitar71 (Nov 8, 2020)

I doubt your daughter will be ripping around hard enough to be affected by the angles of the bike. Really the slacker the bike the better it is at speed and the steeper the bike the better it is going slow. Of course that has it limits but a slack head angle flops around at slow speeds especially when climbing and an inexperienced rider will have a hard time with that. Having better control of the bike will give her more confidence. Having the right size is also part of the equation, maybe a 26” wheel is better.


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## 127.0.0.1 (Nov 19, 2013)

imho
you might be overthinking it...back in the day bikes worked fine, they still do, at any reasonable angle
steep or slack just ride the thing...


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## TheSandwichProtector (Jul 8, 2020)

Thanks guys. For sure I'm overthinking things a bit, lol. Started down this rabbit hole in an attempt to save weight and $. Even though back in the day we rode anything we had...the more my girl enjoys her ride and wants to ride the more fun I'll have as well. She just wasn't having fun pushing the 34lb FS uphills. Complicating everything is the fact that I can't get her on any bikes to try out. I just have to choose one wait a few months for it to get here and hope it works out. If I don't do the Chinese carbon I think I've narrowed it down to the Fuse, Chameleon, Fezzari Wasatch Peak, and possibly Trek Roscoe 7. I found a Chameleon that's available in a size that will work for her even though it's a little more then we had budgeted:
Santa Cruz Chameleon A D 29 Mountain Bike '21
The other part of me wants to try building a frame up cause I've never done and think I'd learn a lot.


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## ilmfat (Mar 10, 2007)

Used to be you could build a bit cheaper than buying complete. That's pretty difficult these days. Not many chop shops clearing out OE parts from teardowns. Cheap frames are vaporware. But the wrenching isn't hard. YouTube helps. The tools you'll need total out around $100.


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## ilmfat (Mar 10, 2007)

2021 Trek Roscoe 8 (Size XS) $1600.00 - bicycles - by owner - bike...


2021 Trek Roscoe 8 (Size XS) I would not be selling this bike if my kid did not have to size up. Please note all the specs and build including dropper post, hydraulic disc brakes, tire size, and...



phoenix.craigslist.org


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## ilmfat (Mar 10, 2007)

Lots of room in the budget for upgrades. But old geo. Mostly depends on what your kid rides.









Diamondback APEX mountain bike - bicycles - by owner - bike sale


Size XS or 12inch frame with 27.5 inch tires. Good for up to 5'2 height. excellent beginner bike for kids. Shimano APEX components. Good condition.



phoenix.craigslist.org


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## ilmfat (Mar 10, 2007)

This is rather compelling:









Ultimate Youth Steel Hardtail - bicycles - by owner - bike sale


I purchased this bike from the original owner thinking that it would fit my son but it is way to large for him. Rather than wait a year for him to grow into it I have decided to sell it and get him...



phoenix.craigslist.org


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## ilmfat (Mar 10, 2007)

I'm jelly of Phoenix Craigslist.









Marin Wildcat Trail 3 - bicycles - by owner - bike sale


have a nice mountain bike thay i bought for my girlfriend but its to big. i bought it for 465 so im not trying to make a killing or any koney really just need it out of our small ass apartment lol....



phoenix.craigslist.org


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## FrankS29 (Oct 23, 2019)

Building up a bike is not that hard and it's a great way to learn about how everything works. 

Most of the bike I built up for my daughter I had sitting right in my own garage already. I picked up wheels, cranks, stem and pedals to finish it up for her.


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## rton20s (Aug 27, 2010)

TheSandwichProtector said:


> Thanks guys. For sure I'm overthinking things a bit, lol. Started down this rabbit hole in an attempt to save weight and $. Even though back in the day we rode anything we had...the more my girl enjoys her ride and wants to ride the more fun I'll have as well. She just wasn't having fun pushing the 34lb FS uphills. Complicating everything is the fact that I can't get her on any bikes to try out. I just have to choose one wait a few months for it to get here and hope it works out. If I don't do the Chinese carbon I think I've narrowed it down to the Fuse, Chameleon, Fezzari Wasatch Peak, and possibly Trek Roscoe 7. I found a Chameleon that's available in a size that will work for her even though it's a little more then we had budgeted:
> Santa Cruz Chameleon A D 29 Mountain Bike '21
> The other part of me wants to try building a frame up cause I've never done and think I'd learn a lot.


I have zero experience with the bike, but you might also take a look at the Polygon Syncline C2. It is just above your budget, but the weight is pretty low, you get a carbon frame and decent component specs.

On the Trek Roscoe, make sure it is a 2022. The bike is all new for this model year. And all Roscoe models below the 7 still use the old frame.


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## TheSandwichProtector (Jul 8, 2020)

ilmfat said:


> I'm jelly of Phoenix Craigslist.
> 
> 
> 
> ...


Thanks for the bike search! For some reason I hadn't even considered looking at the Phx Craigslist yet. I'm very interested in the Marin 3...
What do you guys think would be the best/first upgrades? I was thinking 1x drivetrain and a better front fork.
That Roscoe 8 would be another good option and probably wouldn't need to upgrade anything, although the standover height is a little higher then I'd prefer.


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## FrankS29 (Oct 23, 2019)

TheSandwichProtector said:


> Thanks for the bike search! For some reason I hadn't even considered looking at the Phx Craigslist yet. I'm very interested in the Marin 3...
> What do you guys think would be the best/first upgrades? I was thinking 1x drivetrain and a better front fork.
> That Roscoe 8 would be another good option and probably wouldn't need to upgrade anything, although the standover height is a little higher then I'd prefer.


I personally avoid anything with quick release dropouts at this point. Getting too hard to find quality replacement parts and a lot harder to swap wheels between bikes in a pinch if everything else you have is thru axle.

Thru axle or bust for me...


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## ilmfat (Mar 10, 2007)

Some of the schmancier hubs can swap end caps on the boost stuff to make 141 QR. Dt350 and Hope are 2 we're running now. But I also won't get anything 135/142. Only wheels I have in the old hub width are 24" and smaller.


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## ilmfat (Mar 10, 2007)

I'm a yuge fan of wheel and tire upgrades. If the kid rides smooth and the stock rims aren't too heavy, and tubeless ready, I'd prolly just do tires. And I like rigid B+ and 29ers. Luckily our trails have lots of options for rigid.


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## mikesee (Aug 25, 2003)

Kids don't know any better and couldn't care less if they did.

They adapt and enjoy, in ways that most of us can only dream of. Overthinking it isn't getting you any further ahead.

Two wheels, a seat, and some brakes will bring the smile. Everything beyond that falls into the category of noise to them.


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## ilmfat (Mar 10, 2007)

My daughters could only argue their experience against yours, MC. And I would defo warn them yours has more depth. But they definitely would argue in the areas of wheel/tire weight and compounds. After getting our 10 year old a Journeyman with Gravel Kings, she didn't want to ride the stock i23/2.25 Rangers on the 2018 Timberjack anymore. And the Trail boss tires from the 2019 Deore 29 she refused to ride a second time. I tried em out and I didn't blame her one bit.

That^ said, for the smaller sizes, Mikesee's point stands. Kids will adapt. But they can ride further and faster with better equipment. Putting a Rekon/Ikon on my 10 year old's Small 29er and we went from grumbling to humbling, as she out rode her parents.

And she's just been getting faster.


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## TheSandwichProtector (Jul 8, 2020)

Appreciate all the help and advice everyone! I put a Specialized Rockhopper elite 27.5 on layaway...should arrive in Sept. In the meantime I'm going to keep scouring Craigslist for any acceptable bikes that can be had cheap so I can upgrade as needed.
I'll update after she's on the new bike and ripping some trails.


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## TheSandwichProtector (Jul 8, 2020)

New Bike Update! Had to take an early trip to SLC for a funeral and went down to Hangar 15 where I had the Rockhopper ordered to see if they had anything she could try out for fit. They had a couple of base level bikes with 2x and coil fork in an XS size. She fit them very well but I wanted an air fork, 1x and a little better weight and components. Just so happened they had a Small 29 Scott Scale Contessa for $1400. It's definitely a little bit too big with the 29 wheels but its still ride-able. In a couple of months it'll probably fit pretty well. 1st up will be a dropper post, followed by possible wheel & tire changes. Overall not exactly what I was looking for but she loves it and I can make a few changes to improve the fit as needed.


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