Mountain Biking - bottom crank loose contact

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prusli
01-06-08, 08:37 PM
hi,

I bought MTB Giant Alias last year and found few things unusual and need advice

1) I am getting loose contact feeling from the bottom crank when I shifted to higher speed ie. 5th or above it feels like one ball bearing is missing.. I tried moving crank handle sideway and it is ok.

2) the chain is touching front derrailleur when I am using biggest chainring with smallest gear (highest speed)

are these prob related? how to fix or what adjustments required? thanks

Cypress
01-06-08, 08:47 PM
Uh huuuuh....


Take your MTB Giant Alias to a bicycle shop and have them give it a tune up.
ZeCanon
01-06-08, 09:28 PM
shop is your friend

blue_neon
01-06-08, 10:44 PM
1) Not really sure what your talking about. Its best to go to a bike shop and get them to decipher any problem...much easier then over the internet.
2) Sounds like the derail lure just requires adjustment (the rubbing chain wont cause any damage, just annoying), you could probably do this yourself but if your going to a bike shop to fix problem 1) just get them to have a look.
prusli
01-10-08, 05:51 AM
thx for your feedback.

I took the liberty to fix it myself
1. I opened bottom crank and found metal scrapes / skin. The crank itself, Shimano BB-ES25, is a sealed cartridge unit. Not sure yet if I can open and clean the bearings. I will compare it with new one from bike shop tomorrow.
2. I have also fixed chain prob by adjusting the front and rear derrailleurs

its all fun and good excercise