# Semi-minor Hotrock 16 overhaul going on.



## Dave88LX (Aug 29, 2007)

Looking back, with as much as I've spent on the parts to do these upgrades, may, maybe I should have just sold it and bought something else, but, hell, _in too deep_ now! Plus this is a great learning experience for the both of us. So I will say the frame at least _feels_ light as hell, weighs about the same as the seat/seatpost! That's a heavy mutha!

Going on:

Evolution Bike Co. v-brake clamps
Tektro mini v-brake kit & lever
Truvativ American-to-Euro BB shell adapter
IRD QB-55 68x113 Euro bottom bracket
Sinz 115mm cranks (hoping they're not too long, can always get Turn3 100-110 if needed)
38T chainring (have an MCS, Sinz, and Origin8 to choose from)
18T Excess freewheel
Alex 1000-based rear wheel
Free Agent mini platform pedals
KMC 410 purple chain

I think that's it. It will probably be exactly the same when I am done. :madman::rant::thumbsup:

If anyone has any questions or wants any specific pictures, the next couple few days will be a good time to ask.


----------



## Dave88LX (Aug 29, 2007)

Pedals off.









Chain pin out.









Spinning off that bearing cone nut.









Decided the screwdriver was more work than it was worth.









Bearings are out, crank out!









And here we are. Not shown: "WTF" look from the wife. "What are you doing again?" Good question, wife.


----------



## CJH (Apr 21, 2004)

Dave88LX said:


> Looking back, with as much as I've spent on the parts to do these upgrades, may, maybe I should have just sold it and bought something else
> 
> [*]Evolution Bike Co. v-brake clamps
> [*]Tektro mini v-brake kit & lever


Are the Evolution adapters back in stock or have your had them for a while? Or did you source them from somewhere else?

Pics and some quick comments on how well the brake lever fits tiny hands would be great.

I'm in a similar situation, albeit with not so many parts purchased or stockpiled.

My five year old has lagged behind his 6 year old brother height wise at any given age. Given how the six year old is still a bit stretched out on his Superfly 20 I think I have no choice but to spend some money on our Hotrock 16 for the five year old. Even if I buy him a Cleary 16" bike I'll want to keep the Hotrock as a backup or maybe leave it at our lease.


----------



## Dave88LX (Aug 29, 2007)

I have had them for a while, didn't know they were out of stock. When I ordered them, he was talking about getting some batches anodized, but this was late spring I believe.

How long have they been out for and what's their plan?

I'll be turning in the set screw to fix the reach, but I'll get a pic of the lever.

I have a Redline Pitboss too, but my just-turned-4 daughter prefers the Hotrock over the Pitboss. I don't know if it's geometry or the hand brake, but she's been asking about the handbrake now a little while, and she's starting to try tricks taking her feet off the pedals...so she really needs a hand brake.


----------



## CJH (Apr 21, 2004)

Dave88LX said:


> How long have they been out for and what's their plan?


I called and they said late summer. But then I read on this forum that they were still out of stock in September or so.

I actually feel like a disc brake conversion would end up being cheaper but then I'm forced to get a new rear hub. With the V brake adapters I'd at least have the option of the free coaster mod. And the V brake adapters would probably have better resale value than a home made disc brake adapter. And certainly getting things dialed in will be easier with the V brake adapters.

Decisions, decisions.


----------



## Dave88LX (Aug 29, 2007)

Not sure if Evolution has any in stock, but they are showing in-stock at PorkChop BMX:
Evolution V-brake aluminum mount clamps adapters (PAIR) SILVER

Looks like they carry the anodized ones too.


----------



## slapheadmofo (Jun 9, 2006)

Dave - those pictures are awesome. 

You'll be getting a kick out of those for decades.


----------



## CJH (Apr 21, 2004)

Dave88LX said:


> Not sure if Evolution has any in stock, but they are showing in-stock at PorkChop BMX:
> Evolution V-brake aluminum mount clamps adapters (PAIR) SILVER
> 
> Looks like they carry the anodized ones too.


Thanks. I realize now that I saw that link in the "Resisting the urge to upgrade" thread. I'll follow up and see if they're in stock.

But there is a new wrinkle in all this, however. After months of looking for a used 20" Gary Fisher Precaliber I finally broke down and bought a Superfly 20 for my older son last summer.

Well sure enough a Precaliber 20 just popped up on my local CL for cheap and I jumped all over it. It's a much bigger bike than the Superfly 20 so I'm going to have to give some thought to upgrading the Fisher for my older and naturally taller/lankier son and then hoping my younger and naturally shorter son grows into the Superfly 20 before next riding season gets serious.

I'll take some pics and start a separate thread.


----------



## Dave88LX (Aug 29, 2007)

slapheadmofo said:


> Dave - those pictures are awesome.
> 
> You'll be getting a kick out of those for decades.


Thanks! I love how into it she gets!

So the build is done. I wasn't able to do exactly what I intended to do because of a couple small issues, but the end product is fine, much better than what I started with. Would I do it all over again? Let me add up how much I spent total, compare that to a new similarly-spec'd bike, and I will get back to you. But, as of now, the bike is much improved over what it was.

I recall seeing somewhere the 115mm cranks are too long for a Hotrock 16, and I tend to agree. Even with these pedals that aren't very wide, you can't lean over very much. Turn3 cranks are going to run $126 shipped, Spawn (89 mm, 102 mm) are going to run $70 shipped. At her height, it calls for 115-120 mm cranks, so those options would be a bit short, so the bottom bracket on this bike is a bit low for that application I think.

I intended on running 38/18 (2.11:1) gearing because I had a 38t chainring I took off the Redline Pitboss. I wasn't able to run that because the V-brake adapters interfered with the chainline. I had to settle on 34/18 (1.88:1) using the chainring I intended on using on the Pitboss. So with that said, I probably should have ordered a 16t freewheel instead to get a little more chain clearance off the v-brake adapter.

I tried to use the Rennen 33T chainring but there was some interference with the chain and the Sinz spider. It appeared that the chain was contacting the spider, so with a chainring that small, I may suggest a spider with a slight less diameter. I do like that the chainring is internally threaded.

Truvativ American-to-Euro BB adapter went in without a problem.

IRD cartridge bottom bracket went in no problems. Smooth, spins well. Not one of those "spins forever" ones like you see on YouTube, but, it's good.

Crupi Expert chain is nice and loose.

No issues with the Tektro mini v-brake kit except I needed to bring the lever in a little bit more than the set screw would allow. Got a longer bolt (couldn't find a set screw) and fixed that problem.

Rear wheel setup is good enough for $25. Much much lighter than the stock wheel with the coaster brake. I did have to loosen up the cone nut on the axle a little bit.

The Free Agent pedals are meh, nothing special or fancy about them or the bearings. They are very tight. Maybe they can be loosened up a little.

No complaints about the Redline chain tensioners either.

Fort the hell of it, I also removed the chain guard tabs, coaster brake tab, and kickstand bracket. You know, HUGE weight savings...LOL


----------



## Dave88LX (Aug 29, 2007)

Alright. Did some maths.


PartPriceEvolution Bike Co. v-brake clamps$70Tektro mini v-brake kit & lever$23Truvativ American-to-Euro BB shell adapter$19IRD QB-55 68x113 Euro bottom bracket$28Sinz 115mm cranks$40Kingstar Chainring)$2018T Excess freewheel$21Alex 1000-based rear wheel$31Free Agent mini platform pedals$18Crupi Expert chain$13Redline Chain Tensioner$13Chainring Bolts$10Total:$306

$306 + the cost of the bike ($80 used), so I'm at almost $400 for a Hotrock 16. Course if you go used or have take-off parts laying around or hunt hard for used stuff, you can do things a lot cheaper.

When you figure the Hotrock16 NEW is $240 + $300 in parts ($540 total) to make it still below-par compared to the below bikes, I'd say yeah, not worth it. Compared to the Pitboss, the Pitboss has better wheels/bearings. Weighs 1.6 lbs less with 140mm vs 115mm Sinz cranks. I'm sure there are more pros as well.

Pitboss: 14.6 lbs
Hotrock 16: 16.2 lbs.

The original plan was that if she got into biking, then we'd put the money into a nicer bike. Well, I just kind of got started on getting things for this bike, and, here we are. Damnit.

A brand new Cult CC16 can be had for $347 shipped.
_The 2015 Cult CC16 bike is designed for riders approximately 36-46" tall. The bike features a 6061 aluminum frame with standard headtube drilled for gyro tabs, 1-1/8" fork, Cult inverted topload stem, 2-pc bars with 8" rise, Cult Dehart mini grips, alloy U-brake and lever, 127mm chromoly 3-pc cranks with sealed Mid BB, 25T Cult Member style sprocket, 3/8" sealed cassette hub with 9T driver, 3/8" unsealed front hub, 20H single-wall 16" rims, 16x2.10" tires, Cult 410 chain, Cult 1-pc padded seat/post combo and plastic platform pedals._

A Redline Pitboss can be had for $323 shipped from J&R Bicycles.

Someone try and make me feel a little bit better about myself.:madman: LOL!


----------



## silvascape (Sep 11, 2014)

On the up side I bet she loves it and you got to learn heaps and share the job with you daughter. Now you just need to practice your new riding instruction. "inside pedal up"


----------



## oren_hershco (Mar 11, 2006)

Question to Dave88XL: I'm interested in the weight savings in the crank area.
Is the total weight of the Truvative conversion kit + bottom bracket + cranks + chainring really lower compared to the original 1-piece crankset?


----------



## Dave88LX (Aug 29, 2007)

Yeah she enjoyed it and loves it. I did learn a lot through the process which is good, along with acquiring some expensive tools as well. LOL. Yes she's definitely going to need to learn inside pedal up! 

I don't have a scale to weigh it out, but I've been thinking of picking one up for my own curiousity too. I'll let you know if I get one.

Says the Sinz crank arms are aluminum, but they feel pretty heavy.


----------



## b.r.h. (May 3, 2007)

On the business side, sure it probably doesn't make as much sense. But looking at the pictures (and knowing how interested my 3 yo is in wrenching) I'd say the experience was worth every penny. Well done.


----------



## CJH (Apr 21, 2004)

Dave88LX said:


> $306 + the cost of the bike ($80 used), so I'm at almost $400 for a Hotrock 16.
> 
> Pitboss: 14.6 lbs
> Hotrock 16: 16.2 lbs.
> ...


I think you did good. Both the BMX bikes you listed have U brakes and steeper head tube angles. More importantly, IMO, is BB heights listed at nearly 2" taller. If I saw your bike and the other two for sale used in my area I'd likely be most interested in the Hotrock based on that alone.

Another bike to compare is the Clearly Hedgehog. The company emailed me saying the BB height was 7", about 3/4" lower than the Hotrock 16. I'm skeptical of this based on pictures since the BB center on the Hedgehog is above the hub line, based on the online image. Conversely, the BB center seems to be below the hub line on the Hotrock. I'm guessing Specialized measured to the center of the BB and Clearly measured to the bottom of the shell.

So I'm guessing the BB height on your modified Hotrock is still lower.

Again, I think you did good.


----------



## Dave88LX (Aug 29, 2007)

The Pitboss has v-brakes, but you're right the Cult has U-brakes. In another thread it was mentioned that the u-brakes on the CC were more than adequate though.

Yeah the BB height on the Pitboss is 9.7", Hotrock is 7.4". How does BB height play into things? Stability? BB height on my Hotrock should be the same, since the Truvativ adapter centers the euro BB in the middle of the American shell, and tire size hasn't changed.

How does head tube angle play in?
Hotrock: 70°
Pitboss: 72°
CC16: 74°

Thank you very much!

Took it to the track today and some of the dads were tripping out about the work into it especially the v-brake adapters.

Track day was a success. I'm going to follow-up on the cranks comment, I think the 115mm are a bit long.










She was thrilled to ride the track with her local idol. Super sweet kid this one is.


----------



## CJH (Apr 21, 2004)

Dave88LX said:


> The Pitboss has v-brakes, but you're right the Cult has U-brakes. In another thread it was mentioned that the u-brakes on the CC were more than adequate though.
> 
> How does BB height play into things? Stability?
> 
> ...


I overlooked the V brakes on the Pitboss. Thanks for pointing that out.

BB height does make for a very different feeling bike and I think it would be even more dramatic on the smaller wheel sizes that kids ride. A lower BB feels more stable and gives on the feeling of "sitting inside" of the bike vs sitting on top of the bike.

The steeper the head tube the quicker the steering will be and the less stable the bike will be. I don't worry about HTA as much with my as much as I worry about BB height.

Remind us again how tall your daughter is? Do you have her true inseam length?


----------



## m1tch666 (Jun 20, 2014)

Hi,
I'm doing the v brake conversion to a 2014 hotrock but am having a difficult time with the evolution adapters, it appears the latest drive side chainstay moves from cylindrical to a more oval shape. I think a couple of rubber spacers and longer bolts should solve the issue....anyone else come across this? How did you solve it? You can see the mark where the adapter needs to go...


----------



## Soh67 (Jun 2, 2015)

m1tch666 said:


> Hi,
> I'm doing the v brake conversion to a 2014 hotrock but am having a difficult time with the evolution adapters, it appears the latest drive side chainstay moves from cylindrical to a more oval shape. I think a couple of rubber spacers and longer bolts should solve the issue....anyone else come across this? How did you solve it? You can see the mark where the adapter needs to go...
> 
> View attachment 984860


I'm in the same position with a 2014 hotrock, did you find a decent solution?


----------



## m1tch666 (Jun 20, 2014)

Yip, I had a machine shop take the inside edges off to match the chainstay, fits and works great.


----------

