MTB Techie Manne need help..

[gasant112]

Thanks  Lets check it out..

[Guest Big H]

I have a Shimano Hollocrank (1) Tandem Crankset on our tandem. Do any of you know if Shimano makes an XT or LX tandem crankset in the new Hollocrank II style with the exterior bearings????????

 

There is nothing wrong with the crankset I have got but you all are cyclists and know what happens when the worm starts turning!!!!!!!!!

[Johan Bornman]

If your problem is a scraping chain on the FD and you are sure that your adjustment is right and it's not happening whilst cross-chaining, then it means that your frame is too flexible. Not the BB, the Frame.

 

Fitting other BBs, cranks, pedals and coloured valvecaps won't help. I doubt that any half-decent frame is that flexible and would look for the problem elsewhere. You don't describe under what conditions this scraping happens.

 

JB

[GoLefty!!]

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I have a fairly entry level MTB..( Mongoose ) the crank seems to flex when I stand and pedal.. The chain scraps against the front derailleur... I know on the Dure Ace group set ( Road ) they have a extended bottom bracket which gives some sort of strength to the BB ...  which I think.

Questions

1 Can I upgrade this for something equivalent to D Ace

2 Is there a product like this on the market?

3 What does it cost

 

Help ...

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fairly Entry level MTBs and road bikes tend to flex quite  a bit; they're not that well designed.

 

Many years back I experienced similar chain rub on my Diamond Back Axis MTB (Thin steel frame).

I solved it by taking a screw driver and bending the inner and out plates of the derailleur apart by a mm or two.

The next step was to angle the deraileur so the the front pointed in toward the frame slightly.

Reseting the limit screws accomodated the range of travel and the problem was solved.

 

The toe in of the derailleur had a positive effect of making the up shifts more positive and faster. The wider cage now accomodated the chain better.

 

Worth a try but don't be using a crow bar. a few mm is enough.