Garthe Posted October 11, 2014 Report Share Posted October 11, 2014 My son is a tall 10 year old. He's 155cm and weighs in at 50kg, has raced bmx for the last four years, can bunny hop the hell out of his bmx street or race bike and has a great vertical leap. Aidan has also been riding a kids Echo Mod for the last three years. He has all the basic trials bicycle skills nailed and is starting to work on rear wheel pedal kicks. He's outgrown his Echo kids mod and I'm trying to figure out which bike to get him next. Seems like there is two different groups of modern BB height bikes in the Mod class, 50mm or 80mm . I was considering getting him a Monty 221 Ti, which has the lower ranged BB height. Let him ride that for a year or so and then get him one of the high BB bikes. The Monty will also weight in at around 9.5kg. Or, I go right for one of the high BB bikes and skip the Monty 221 Ti. These high BB bikes also seem to weigh a little less the the lower BB, slightly older bikes. Skills goal for Aidan's bicycle trails is UCI Youth Worlds level. Although that will take years to achieve. Moto trials will also be phased in, in the next year or so. QUESTION: What are the pros and cons of BB height? From the rider facts I've given, should I get Aidan a low or high BB bike next? Thank your for your time and help, Jim Quote Link to comment Share on other sites More sharing options...
isitafox Posted October 11, 2014 Report Share Posted October 11, 2014 I wouldn't base a bike purchase on what BB height the frame is, you want to consider the rest of the geometry as well. Has he competed in any comps already? Probably be better off getting to a local comp and asking if he can try a few of the other riders bikes to see what he feels comfortable on, obviously the bar/stem choice plays a big part but it'll help. Also the height of the BB has no bearing whatsoever on the weight of a frame, it's just a case of as the years are passing mod BB heights are going up and the frame weights are going down. I used to ride a mod with a +55 BB a few years ago and I know I wouldn't want to go any lower than that. Quote Link to comment Share on other sites More sharing options...
Garthe Posted October 11, 2014 Author Report Share Posted October 11, 2014 He was ridden in two trials events. Both on natural terrain. The events are moto trials events and they have a bicycle class. However, I live in the States. Bicycle trials participation is extremely low or nonexistent. Finding other bikes to try is near impossible. I've closeness the 1000mm wheel base and 350mm CS range. I then believe, I can dial in the stem and bars from there. The BB height of the Echo kids Mod is 45mm. He been on that bike for the last three years. The Monty 221 Ti has the same BB height as the kids mod. Thats why the 221 stuck out to me, in the selection process. Quote Link to comment Share on other sites More sharing options...
dezmtber Posted October 11, 2014 Report Share Posted October 11, 2014 I am a short 30 year old. Probbably about close to the height of a ten year old. 5' 5 and a bit. I found that my onza with lower bb was a litte easier to track stand on two wheels. But wasn't quite as nimble on the back wheel as my newer rockman. I found the higher bb impoved my riding loads. I would say my balance is very good during track stands, but I fall short on balance on the back wheel, mainly due to panicking. I would say if your little lad has good balance already then go with the high bb, if not then maybe go with the lower. Quote Link to comment Share on other sites More sharing options...
isitafox Posted October 11, 2014 Report Share Posted October 11, 2014 Wheelbase doesn't really make much of a difference, the measurement you want is the reach (distance from the centre of the BB to the top of the headtube). In terms of UCI riders you'll find they ride high BB frames as most of the work is performed on the rear wheel and a high BB makes a bike easier and more stable to control on the rear. A good example is in here, Adam is about 10 or 11 and his new frame is 985 wheelbase and +85mm BB height. If it were me buying then personally I would avoid Montys in general and go with an Echo/Koxx/Onza frame for him. 1 Quote Link to comment Share on other sites More sharing options...
Disc.Jokie. Posted October 12, 2014 Report Share Posted October 12, 2014 firstly you want duel disc. its a lot easier to maintain and (not in my opinion, but neibourgh, nearby people's opinion) sounds better. discs also work best in all conditions. secondly, seens he is ten he problerbly will not be very strong compared to adults/teenagers so i would try find a reasnoble light bike for him to make it easier. id guess 8-9 kg give or take .5kg thirdly it will be easier for him on a higher, and shorter bike. 990 or shorter and 80 or higher. it all depends on budget really to be honest, and the difference are not very large at all. Quote Link to comment Share on other sites More sharing options...
Robin M S/c Posted October 14, 2014 Report Share Posted October 14, 2014 Don't go with the monty. Too long and low. Adam has been on a GU all season which was 985 long, 595 reach and +85. His new onza is the same except 600 reach. Before that he had a prototype that was 970 long and +55. The higher bb has given him far more control on the back wheel and if your son is wanting to aim at UCI events a higher bb is the way to go 1 Quote Link to comment Share on other sites More sharing options...
Garthe Posted October 18, 2014 Author Report Share Posted October 18, 2014 Thank you very much for all your help gentleman! I'm ordering all the parts on Monday and will have it built up by the weekend. I decided on a Echo Lite. Specs are as follows: Wheelbase: 995mm Chainstay Length: 350mm BB Rise: +80mm Head Angle: 71° Centre of BB shell to top centre of head tube: 590mm I have a very strong feeling this frame is going to work out for Aidan. I also have the ability to use some of the parts from his Echo kids mod for this project. He'll be using bb7 for right now. But, I'll be updating the brakes next. He's been looking cramped on his kids mod and I want to get him on the bigger frame ASAP. Again, thank you for all the replies. I'll update you guys with some pictures, of him on his new bike as soon as I can. Cheers, Jim 1 Quote Link to comment Share on other sites More sharing options...
Jake. Posted October 18, 2014 Report Share Posted October 18, 2014 Look forward to seeing how he looks on the bike what stem and bars did you go for? Quote Link to comment Share on other sites More sharing options...
Garthe Posted October 19, 2014 Author Report Share Posted October 19, 2014 Robin, what range in tire pressure are these young boys (10 -11 years old) using? And also, your sons You Tube videos have been invaluable to us, here in the States. My son watches them over and over and over...lol. We hope to have the pleasure of meeting both of you someday. Cheers, Jim Quote Link to comment Share on other sites More sharing options...
Robin M S/c Posted October 20, 2014 Report Share Posted October 20, 2014 Hi Jim, glad you are enjoying the videos. There are some more on the vimeo Tartybikes channel as well. Adam is running 20-21 psig on the front and 15psig on the 19" rear. Quote Link to comment Share on other sites More sharing options...
Garthe Posted October 28, 2014 Author Report Share Posted October 28, 2014 Just got the new Echo built up today, Aidan looks amazing on the bike. He's only ridden the bike for about 40 minutes. But, looks so comfortable riding it. He looks like he's working less and doing more. The 80+ bb height was the only way to go... I'll submit photos in the next day or so. I might need a opinion on bar/stem adjustments. Although, I think I'm very close. Quote Link to comment Share on other sites More sharing options...
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