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Post by lincolnimp on Nov 3, 2010 17:48:00 GMT
Hi This is our first venture into gravity sports and we have decided to go down the sidecar route. Can anyone please offer some advice on wheel size? I like the look of the machines built using mini moto type wheels and frames but we are unsure about the speed these wheels will give. I have looked at the results from events but cannot identify what design of machines teams are running. Advice on anything relating to sidecar building will be gratefully accepted. Thanks JP
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Post by shutz on Nov 3, 2010 18:10:03 GMT
Hi JP and welcome to the forum. Like you we are new to all this but looking at the carties the wheel of choice seems to be the 20" bmx wheels, due to strength and available tyre choice plus its fairly close to the maximum wheel size. The cheats winning sidecar at cse this year had something similar i think. But im sure someone can confirm this. Anyway thats what we are using for the sidecar plus you can get disc compatible if you look hard enough Shutz
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Post by Scottish Cartie Association on Nov 3, 2010 18:39:52 GMT
The minimoto based sidehacks seem to be slower than the BMX based ones and they're normally well off the pace. I don't know of a minimoto hack winning anything.
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Post by Scottish Cartie Association on Nov 3, 2010 18:47:12 GMT
BTW: On maximum wheel size. 550mm is not actually a recognised wheel size. That size was chosen because it's '20" plus a little bit', to avoid problems at scrutineering. Any standard 20" wheel will be comfortably within the limits.
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Post by leew on Nov 3, 2010 22:30:21 GMT
Just for those who don't already know about the confusing world of wheel sizes, there are two wheel sizes known as 20 inch. ISO 406 which is the common BMX size and by far the most common of the two and the less common ISO 451 size. Either of these sizes could be used for a sidecar providing you make sure you use rims, tyres and tubes which are compatible (a 406 tyre will not fit a 451 rim and visa versa). I would recommend ignoring the traditinal 'inch' sizes as they can be confusing and rely on the ISO/ETRTO sizes when choosing rims, tyres and tubes. Tyre choice for the 451 size is more limited and 451 tyres are generally fairly skinny, 37mm width is the widest I know of and thus would still comply with the 550mm max size. The widest tyre for the 406 size I know of is the 60mm Big apple which would result in an overall diameter of 526mm
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Post by Scottish Cartie Association on Nov 3, 2010 23:03:29 GMT
Lee's post there demonstrates why the max wheel diameter is quoted as 550mm - you can use any of the nominal 20" wheels and still meet the spec'.
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Post by lincolnimp on Nov 4, 2010 12:41:23 GMT
Thanks for all the quick replies it now seems that things are not quite as simple as they first look. I have seen some BMX wheels with extra spokes (can't remember the exact number). I think these are designed for jumping etc. so should be strong as we are not going to be a light outfit! Where do I look for wheels to take discs? and are disc brakes worthwhile? Thanks again JP
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Post by shutz on Nov 4, 2010 13:13:50 GMT
if it helps these are what we are using www.cyclesuk.com/371-482735Bear in mind that like we said we are new to this to so they are untested as yet on the sidecar (still getting built) but fingers crossed should be ok.
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Post by Organgrinder on Nov 5, 2010 13:00:49 GMT
A lot of the soapbox boys use BMX rims laced to mountain bike hubs with disc brake flanges.
I'm far from convinced that the extra cost and complexity of disc brakes is worth incurring. We have good quality V brakes on our outfit and she stops just fine. Spend your cash on strong 48 spoke wheels with aluminium twin wall rims and top quality bearings would be my advice.
Just to throw a spoke in the wheel, if you will pardon the pun, who thinks all the wheels should/need to be the same size? They are all carrying a different amount of weight and have to endure different stresses on a sidecar. With an outfit only having three wheels it shouldn't be difficult to get them all to sit on the road at the same time, irrespective of their size.
Thoughts, Gentlemen?
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Post by Scottish Cartie Association on Nov 5, 2010 13:11:06 GMT
I agree about the brakes - our front & rear V brakes work fine.
I don't think there is any particular need for all the wheels to be the same size, although it makes life a little easier when it comes to stocking up on spare tubes, tyres, etc.
We have 20" wheels on the bike and 18" on the car, but that's just because those were the wheels I happened to have in the shed.
I'm thinking of putting a 16" wheel on the front as, with a 20" on the back we'll be going down hill even when we're on the level. Should go much faster. Sneaky, huh?
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Post by Organgrinder on Nov 5, 2010 13:27:54 GMT
I thought I was the only one to have spotted the potential for free speed offered by a 16" front wheel - just a bit concerned that heavy braking may overheat the smaller rim of a 16" wheel and cause an inner tube failure - you could always run tubeless - there are several "ghetto" solutions to running tubeless tyres on conventional rims on the mountain bike forums, but all involve the use of gunge to create a seal, which may negate most of the advantages for us?
Why's life so complicated?
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