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Discussion Starter · #1 ·
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Build Specs and Cost- ~$600:
Cujo 20" Plus Bike - $440
Spawn 127mm Cranks - $65
Shimano 395 Hydro Brakes - $70
Shimano UN55 BB - $20
Stans Schrader Tubeless Valves - $16
Sram X9 10 speed - $0 (Old takeoffs)
ESI Grips - $0 (Old takeoffs)

21.5 lbs on the scale with pedals

I originally planned to build up a Gary Fisher 20" for my son that is real similar to a Trek Pre-caliber. I was going to do the Suntour 20" air fork, spawn tubeless wheels / tires, plus the other upgrades I did here, but a few things pushed me in this direction. The cost was nearly the same and the GF was going to be heavier, but the biggest factor was watching big sister ride a 24" Plus Specialized RipRock and roll right over roots on a few uphills that were hanging him up on the Gary Fisher. The plus tires swallowed up the roots for her at slow speed and stopped him dead in his tracks.

One thing pretty cool is the Cannondale comes with a 7speed Freehub which let me upgrade the drivetrain without swapping a hub. You can fit 9 of the cogs from a 10 speed setup and adjust the limits to work fine.

In my opinion the Shimano hydros are a no brainer upgrade and the new BB was a recommendation from the shop that I never considered about but for 20 bucks seemed like a good call. Wheels setup tubeless no problem and we are running them at 10 psi. I cut the chewed up end off my grips and put them on the kids' bike and they all like the little bit of extra cushion from the ESI's

First ride we knocked out 5 miles of trail in 45 min and he noticed immediately he could ride up things he couldn't before. Downhill he never had much issue before since the speed was there and he just bounced right over everything.
 

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Cool build, my son will probably be getting one soon. I think the only change I will make off the bat is trigger shifter and tubeless. How did the wheels and tires set up?
 

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Discussion Starter · #3 ·
The bike shop was excited to trick this one out so they did the setup for me. He said they worked great and they were still holding 10 psi 5 days later.
 

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Does your son or daughter have any trouble riding the plus size tires uphill. I can see where the would definitely benefit downhill. I have a seven year old boy and girl and looking at either upgrading their 20” bikes they have now buying them a new 20” plus. Seems you got the weight down pretty good. They both have Haro flightline 20s and weigh about 23.5 each. I figure they could get 2 more years out of a plus size bike and if it gives them confidence it would be worth it. Nice build by the way!!
 

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Discussion Starter · #5 ·
I have found the plus tires improved the uphill riding for us because they were getting hung up on roots more than inability to pedal. The plus size gives a little bigger rollover and the low pressure tires seem to swallow up the bumps more than bounce back and stop them in their tracks.

That being said, we don't have mile long climbs. These are short, moderately steep 30-100ft elevation changes.

My kid is 7 yrs old riding this, but also pretty short. His sisters were on 24's or about ready at that age.
 

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Just fondled one of these in the LBS. WHY WHY WHY do they (anybody) continue to spec those horrible Shimano Revo twisters? They are tough for me to twist, never mind my 8-9 year old. The display window is also terribly small. I can see that going wrong in so many ways.

Otherwise the bike seems really solid. No stupid boat anchor suspension fork or needlessly complicated front derailleur. Seriously tempted.
 

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Discussion Starter · #8 ·
Still happy with ours. I actually went back to the 110mm stock cranks. Pedal clearance is an issue with the longer 127 spawn cranks on this bike. Down to about 6-7PSI in the tires as well.
 

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I picked one up for my son about a month ago. I switched out the grip shift as soon as we got home. I put an old 8 speed trigger shifter (index is the same as 7 speed)on it and he took to it right away. He loves the bike and is progressing in ability really quickly. My only complaint is that the brakes work so well I will be looking for a new back tire soon :thumbsup:
 

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Does your son or daughter have any trouble riding the plus size tires uphill. I can see where the would definitely benefit downhill. I have a seven year old boy and girl and looking at either upgrading their 20” bikes they have now buying them a new 20” plus. Seems you got the weight down pretty good. They both have Haro flightline 20s and weigh about 23.5 each. I figure they could get 2 more years out of a plus size bike and if it gives them confidence it would be worth it. Nice build by the way!!
My girls also liked the plus tires, both up and downhill. We have the Riprock (first 20 and now 24) and both sizes the Specialized Rolller 2.8 tires set up tubeless easy. They are also quite light tires, even compared to many “normal” size tires.
You can buy the Specialize Roller 2.8 or Kendra Slant Six 2.6 aftermarket, which my friend did, and fit them on his kids regular bike.
 

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JWHY WHY WHY do they (anybody) continue to spec those horrible Shimano Revo twisters? They are tough for me to twist, never mind my 8-9 year old.
That's funny, I find the Shimano RevoShift twisters to be quite easy to turn as did my daughter. She greatly preferred them to trigger shifters. Many 8 year olds do not have the thumb strength (or reach) to use your average Shimano 7/8 speed triggers. I find good twist shifters to be a good choice for kids' bikes.

I've found the RevoShift to be the easiest to turn of the various other offerings from SRAM, MicroShift, no-name brand, etc...

https://www.youtube.com/watch?v=EvzLOt1599U makes a good point in that the older Shimano triggers (ie, those for 7/8 speed that would be used on kids' bikes) require you to move your index finger off the brake to up-shift. Some kids I've seen don't like not always being ready to brake if they get nervous.
 

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I switched out the grip shift as soon as we got home. I put an old 8 speed trigger shifter ...
I'm curious, did your son try the grip shifters first and preferred trigger, or did you switched them out purely on your own preference?

I've seen many kids that preferred the twist shifters and that prevented me giving them better hand-me-down parts.
 

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He tried and struggled with the grip shift at the bike shop, and on our first ride at home. He took to the trigger shifter in the first minute once it was adjusted.
 

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Hi all, do you think the specialized 20x4 or 20x3 tires that come on specialized Fatboy 20 or on the salsa timberjack will fit on this bike? Thank you
 

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My son didn't get on at all with Revoshifts.. same with a few of his friends, but he and his friends get on fine with the rapidfires we replaced them with.

I guess it's different for different children...
 

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Came here looking for the tire clearance info as well, thanks! Was curious if I could swap some tires over for winter/fatbiking. My daughter is so light, the 2.6's are probably just fine anyway lol.

My daughter did not get along with the twist shift either. She had the trigger shifters down inside of the first two rides.
 

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Thread getting a little stale but great info so far!! My almost 5 yo son has about 50 miles on his in last couple months. Just put on shimano zee 10 spd shifters and derailleur, 10spd -1 xt cassette, sram pc1071 chain and avid bb7 brake levers. Next is tubeless.
 

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Picked ours up yesterday and was up late working on it.

For those that care about numbers:

Stock bike was 22.7 lbs (although there was an extra bag of reflectors not installed that weighed 74g)

- Seatpost: 297g
- Saddle: 263g
+ Spawn Brood Pivotal saddle + 125mm seatpost: 297g

Seatpost clamp 26g

- Pedals 277g
+ Tioga Dazz Lite Pedals 238g

- Rear QR skewer 65g
+ Ti rear QR skewer 27g

- wheel reflectors 34g

Sunrace 7 speed 11-34 cassette 295g
Sunrace cassette lock ring 14g

- Spoke protector 30g

Rear rotor bolts 13g

- Rear rotor 128g
+ Ashima Ai2 clone rotor 70g

- Stock 110mm cranks w/ integrated 30t chainring 500g (335g right / 165g left)
+ Spawn 102mm cranks w/ USA made 24t chainring 431g (before I removed the bash guard and spacers - should be about 40-50g lower now)

- Stock 68 x 119mm bottom bracket 337g (includes nuts / bolts)
+ Origin8 68 x 107.5mm bottom bracket 221g
+ Crank arm bolts 29g

Stock BB felt super gritty, despite appearing to be installed correctly and having enough grease.

The 107.5mm was all I had sitting around, but seems to have good frame clearance and a good chainline as long as I remove the bash guard from the Spawn cranks.
With the bash guard and spacers the chain looked a little too close for comfort to the tire. Debating on keeping it as-is for better q factor vs ordering something closer to stock to allow for using a guard.

Rear wheel with just tire and tube 1844g

Will post more as we do more. My son is already clamoring for levers to shift (even I find it hard to turn the grip shift) and complained he can't reach the brakes with the current reach adjustment.
 

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Some more updates:

- 75mm Stem 145g
+ 40mm Wren stem 70g

- Top cap & bolt 16g
+ Origin8 integrated cap & bolt 5g

- Bar 278g
- Junit bar 260g

- Grips 78g
+ Junit grips 71g

- Stem spacers 14g
+ FSA Polycarb spacers 5g

Headset - It's listed in the specs as "FSA, Alloy, 1-1/8" Ahead, integrated"
From inspection, the outer diameter of the headset tube is ~50mm and it looks like an FSA No. 10 (93g) -- which would mean it might be possible to swap the lower with an EC44 and put in something like the Junit 120mm fork.

Chain 276g

- Shimano Tourney 6/7 speed rear derailleur 315g
+ XT 9 speed rear derailleur 224g

Kenda Slant 6 20x2.6 Tires 600g each

- Shimano grip shifter 75g (weight not including generic cable & housing)
+ Shimano 7 speed trigger shifter (optislick cable & SP41 housing)

- Kenda 2.1-2.4 rear tube 216g
- Stock rim strip 23g
+ Tubeless schrader valve 13g
+ ~3oz Stan's Sealant 90g
+ 12mm Stan's Tape

- Kenda 2.1-2.4 front tube 224g
+ Forte 1.75-2.1 tube 126g

With a lot of fuss and effort, I tried tubeless on the rear -- leaked some sealant through the rim welds and burped some on the first trial ride. From the soap bubbles I see around the bead adding a little more this morning, I'm a little worried about whether or not this is going to hold long-term.

Went ahead and just used a lighter tube from Performance Bike for the front. In hindsight, I'd have just put in the lighter tube in the rear too if I had realized the weight difference was going to be so small.

Weights without rim strips:
Rear wheel 998g
Front wheel 785g

Hubs are listed in the specs as Forumula 7-speed freehub, disc. Looking at the Formula site, the closest looking set of QR hubs I can find are:
DC-20 Front - 100mm Cup & Cone, 274g
DC-22 Rear - 135mm Cup & Cone, 486g

Looking at the weights for those, it comes pretty close when I subtract those from the front / rear -- (512g / 511g).

Making a rough guess of 5g each * 28 spokes, that would put the rims at roughly 370g

Rims are listed in the specs as labeled as Cannondale C4 Disc double wall 29mm innner width, 28H.
They're labeled with stickers stating Shining Rims DC5.0 Disc with dimensions of 406x29. I don't see anything that matches exactly on the Shining Rims site.

That makes for another ~445g dropped in the most recent round of changes, so ~1.1kg total off stock.
 
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