I bought my son a Scott Scale RC Jr for his 9th birthday. He still fits his 20" well but will soon be too big for it (52" @ 61lbs).
The Scott is nice out of the box, but there were a few things I wanted to do to make it more kid and height friendly, such as, convert to 1X setup and change cranks lengths.
Some initial thoughts on the RC Jr;
Frame - The weight with headset (~100g), and seat clamp (~15g) came in at 1504g or 3.31 pounds which is heavy. They could have easily made it less than 3 pounds. There's a super thick and large kick stand plate right behind the bottom bracket. Why?
Fork - Finally an air fork! Unfortunately, it's heavy at 1839g or 4 pounds. It does come with an aluminum steer tube and magnesium lowers but the thing is still a tank. The travel is limited to about 50mm because of the strong negative springs. I've varied the air pressure from 50-100psi but there's not much difference. The air chamber in the damping/air spring unit is just too small for any significant change.
I've already dissected the whole fork. Removing the negative springs will allow the fork to have 80mm of travel but removes all small bump compliance. There's a whole lot of stiction without the negative springs.
I'll let him try it for a few rides and see what's more important; a cush ride or more travel. I think more travel will prevail. In the end, I'll probably reduce the negative spring which is comprised of 2 stacked coil springs (heavy and light) and increase the travel to 75mm with an added top out bumper.
Syncros Components - Scott bought Syncros which is why you now see them on the bike. The parts are ok but not the lightest options. Probably part of the 2 pound increase over the previous year RC Jr. The other weight increase was probably because of the fork. The Syncros handlebars weighed in at 290g! That's insane for a kids bar. I swapped it out for a Truvative T30 @ 162g cut to 560mm.
Drive Train - I liked the Shimano hardware. Looks like they put some thought into which components should go where. The 3X cranks are too long. I understand why they did it. No one makes a 3X crankset less than 165mm though I would think at the volume they are buying at, someone would redrill/tap new holes. It would have been cool if they would have removed the 44T and spec'd a bash ring. Also, the two inner chainrings are steel.
Wheelset - The pair came in at 1632g w/ rim liners. Not bad though about the same as a standard 26" wheelset. Also, the tires are not Kevlar as spec'd on their page. They came in at 548g a piece. Not bad though will probably change to Kenda SB8's @ 425g.
Brakes - Fairly standard brakes. Not as smooth as an Avid 7 or XT but that may be the brake liners which are Jagwire. I thought the Jagwire brand was supposed to be decent but I may change them to get smoother action. I also removed the lever return springs but that didn't help with the action.
Changes;
Drivetrain - Converted to a 1x10. I could have used the stock stuff but I wanted a 36T cog. I could have achieved this 3 different ways;
1. Bought the HG61 12-36 but it's a boat anchor @ 424g.
2. Bought the HG61, remove the 36T cog and mate it with the stock XT cassette and remove the 11T inner cog.
3. Buy a 10spd drive train.
I ended up going with the 10spd because the cost differential was only the rear derailleur @ $60 and chain @ $31. It alleviates me from the boat anchor HG61 or home brewing an 9spd XT 36T hybrid.
Crankset - Too long and too heavy. Swapped out for a simple Sinz single 34T. I had a spare Ti bottom bracket so I threw that in the mix too.
Weighty stuff - I swapped out the handlebars because of weight but that's about it.
Enough with the banter already, here are pics and weights.
Stock RC Jr. bike
Removing parts
After changes with 1X setup.
New gear ratio's. Highlighted is the 34T. I toyed around with getting a 104bcd crank and getting a 30T front but didn't want to drop any more dough.
Weights
The Scott is nice out of the box, but there were a few things I wanted to do to make it more kid and height friendly, such as, convert to 1X setup and change cranks lengths.
Some initial thoughts on the RC Jr;
Frame - The weight with headset (~100g), and seat clamp (~15g) came in at 1504g or 3.31 pounds which is heavy. They could have easily made it less than 3 pounds. There's a super thick and large kick stand plate right behind the bottom bracket. Why?
Fork - Finally an air fork! Unfortunately, it's heavy at 1839g or 4 pounds. It does come with an aluminum steer tube and magnesium lowers but the thing is still a tank. The travel is limited to about 50mm because of the strong negative springs. I've varied the air pressure from 50-100psi but there's not much difference. The air chamber in the damping/air spring unit is just too small for any significant change.
I've already dissected the whole fork. Removing the negative springs will allow the fork to have 80mm of travel but removes all small bump compliance. There's a whole lot of stiction without the negative springs.
I'll let him try it for a few rides and see what's more important; a cush ride or more travel. I think more travel will prevail. In the end, I'll probably reduce the negative spring which is comprised of 2 stacked coil springs (heavy and light) and increase the travel to 75mm with an added top out bumper.
Syncros Components - Scott bought Syncros which is why you now see them on the bike. The parts are ok but not the lightest options. Probably part of the 2 pound increase over the previous year RC Jr. The other weight increase was probably because of the fork. The Syncros handlebars weighed in at 290g! That's insane for a kids bar. I swapped it out for a Truvative T30 @ 162g cut to 560mm.
Drive Train - I liked the Shimano hardware. Looks like they put some thought into which components should go where. The 3X cranks are too long. I understand why they did it. No one makes a 3X crankset less than 165mm though I would think at the volume they are buying at, someone would redrill/tap new holes. It would have been cool if they would have removed the 44T and spec'd a bash ring. Also, the two inner chainrings are steel.
Wheelset - The pair came in at 1632g w/ rim liners. Not bad though about the same as a standard 26" wheelset. Also, the tires are not Kevlar as spec'd on their page. They came in at 548g a piece. Not bad though will probably change to Kenda SB8's @ 425g.
Brakes - Fairly standard brakes. Not as smooth as an Avid 7 or XT but that may be the brake liners which are Jagwire. I thought the Jagwire brand was supposed to be decent but I may change them to get smoother action. I also removed the lever return springs but that didn't help with the action.
Changes;
Drivetrain - Converted to a 1x10. I could have used the stock stuff but I wanted a 36T cog. I could have achieved this 3 different ways;
1. Bought the HG61 12-36 but it's a boat anchor @ 424g.
2. Bought the HG61, remove the 36T cog and mate it with the stock XT cassette and remove the 11T inner cog.
3. Buy a 10spd drive train.
I ended up going with the 10spd because the cost differential was only the rear derailleur @ $60 and chain @ $31. It alleviates me from the boat anchor HG61 or home brewing an 9spd XT 36T hybrid.
Crankset - Too long and too heavy. Swapped out for a simple Sinz single 34T. I had a spare Ti bottom bracket so I threw that in the mix too.
Weighty stuff - I swapped out the handlebars because of weight but that's about it.
Enough with the banter already, here are pics and weights.
Stock RC Jr. bike
Removing parts
After changes with 1X setup.
New gear ratio's. Highlighted is the 34T. I toyed around with getting a 104bcd crank and getting a 30T front but didn't want to drop any more dough.
Weights
