Middleburn Rs7 Superpro Trials Cranks

[echo v onza]

i have had these cranks along with an echo isis external bottom bracket on my onza for about 4 months, i am running a twelve tooth sprocket on the back which for me is the perfect gear ratio(when it works)since i have had them on my bike i have snapped several different kmc chains many times over, and my bike shop has told me that the sprockets i am running are to small and if i were to put an extra two or 4 teeth on the front and back i would have the same gear but will eliminate the chain snapping problem IS THIS TRUE ANY HELP WILL BE MUCH APPRECIATED.

[TheMunn]

Kinda true yeah, although if you bought a chain that is designed to work around smaller sprockets then you shouldn't have a problem. But you could get a larger rear sprocket to improve the gear ratio for riding trials on, you also need to check the chain is installed properly too.

[adam trials]

make sure you have loads of tension on your chain because i had that sort of problem on my old bike until i added loads of tension lol

[Rupertbear]

what sprocket are you running on the front at the moment?i dont think adding 2 or 4 on each sprocket will work because youde end up with a higher gear.

[echo v onza]

make sure you have loads of tension on your chain because i had that sort of problem on my old bike until i added loads of tension lol

i am running a standard dmr chain tensioner it is complete crap always loses tension do you know any better tensioners plus how do you get deralier to hold your chain,because everyone is running deraliers and i cant get mine to work??

what sprocket are you running on the front at the moment?i dont think adding 2 or 4 on each sprocket will work because youde end up with a higher gear.

its a 16 tooth middleburn the one which is sprocket and bashgaurd as one they are not separate, but in theory if you add the same amount of teeth to the front and back you should get a similar if not the same gear ratio

these are the cranks etc.

http://www.tartybikes.co.uk/product.php?id=184

Edited December 3, 2006 by echo v onza

[chrishayton]

your snapping chains because your running 16-12. thats way too hard. 16-14 is what you should be running

[Ali C]

16-14 is the usual gear as chris said. It is tru that the larger the cogs the fewer chains will snap (its all about leverage) so 18-15 is easier on chains, but 20-17 is even better than that.

[stug45]

i run 22-18 is this even better?

[brealy]

run 13-16 ohh and to make your chain last get it alligned so it does not rub on the bashring

[echo v onza]

ok guys, thanks for your help but now i need some advice on what bashguard and front sprocket to replace the originals with any parts you guys would recommend. you can probably guess from the top half of my thread that the cranks are the screw on type i don't no the proper name but they are not the standard mountain bike 4 or 5 bolt allen key cranks, i only put this so some guy doesn't have a go at me or something for not putting enough description

thanks for your help

[RobinJI]

Middleburns arent screw on there a spline fit, theres a lockring behind your ring/bashguard combo that unscrews then the ring/bash slides off. Because of this fitting, the only thing you can get to replace it is either a Middleburn Pro-trials guard (not super-pro, just pro) there £30 off CRC then you need a sprocket to go on it, either a 20t 5arm CD sprocket or a 22t. These are about £12-15 I think...

As for the gearing, personaly I'd suggest trying something a little lower. You can work out what would be the same by deviding the frotn sprocket by the rear, so 16/12=1.3333, so the same gear with a larger front ring would be, 20/15=1.333333.

(CRC = www.chainreactioncycles.com)

Oh yeah, is this mod or stock?? if its a mod then Id say to try a slightly higher gear (number higher than 1.3333, something like 1.5) if its a stock I'd say try something lower (maybe 1.2ish)

Edited December 4, 2006 by Dont you Just Hate it When...

[echo v onza]

Middleburns arent screw on there a spline fit, theres a lockring behind your ring/bashguard combo that unscrews then the ring/bash slides off. Because of this fitting, the only thing you can get to replace it is either a Middleburn Pro-trials guard (not super-pro, just pro) there £30 off CRC then you need a sprocket to go on it, either a 20t 5arm CD sprocket or a 22t. These are about £12-15 I think...

As for the gearing, personaly I'd suggest trying something a little lower. You can work out what would be the same by deviding the frotn sprocket by the rear, so 16/12=1.3333, so the same gear with a larger front ring would be, 20/15=1.333333.

(CRC = www.chainreactioncycles.com)

Oh yeah, is this mod or stock?? if its a mod then Id say to try a slightly higher gear (number higher than 1.3333, something like 1.5) if its a stock I'd say try something lower (maybe 1.2ish)

its a stock and

your right, sorry my bad thanks for the help but are they really my only options, you would of thought for 160 pound of there abouts you would be able to fit wh

Edited December 4, 2006 by echo v onza

[RobinJI]

Nah, sorry, I think that really is it for trials. There amazing cranks, but pretty specific. You can get Various spiders but I don't see how they would help you, as you're not gunna go bigger than 22t and you will want a bash, so its easier to get the Pro-trials bash than say, a DH spider and a separate bash ring.

List of most middleburn products.

As of yet no-one but middleburn make anything to fit them, but I believe Ali C is planing on producing some 18t versions of the Super-pro trials guard.

Also there are a few small companies such as Iolo and Leeson who will machine you pretty much any design you want.

Edit: sorry, forgot to actualy put a link... :$

Edited December 4, 2006 by Dont you Just Hate it When...