Advice needed on gears

hamael

i am quite novice when it comes to repairing bikes. I should be better, but I lack the knowledge and tools!

What's happening is my bike is jumping in gear numbers 5 and 6 (out of a total of 7). I took my bike to a shop, and they said for a new cassette, chain and chainset, with labour, it would set me back around £110. Another shop quoted me £75, but pointed out I had a freewheel, not a cassette - they also pointed out my deraileur is slightly bent, but they could probably straighten this up for me.

So I'm sat here wondering do I cough up the £75, or try and do the work myself and buy the tools and parts that I need. I think maybe I could source the parts on eBay cheaper, but i don't have a clue what to buy! This is where I hope BikeRadar can help me!

What I can see on my bike, are the following markings:

• Cassette/freewheel - Shimano MegaRange Super-Low 13-34T
• Chainset/pedal - SR Suntour
• Deraileur - SRAM SX4

I hope somebody can tell me what I need, and what I need to do. If you need pictures of any parts, let me know and I'll try to get what you need.

mrmonkfinger

its probably a fair assessment by the shop... freewheels can be a complete pain to get off - just be prepared.

you'd need (at least):
a chain whip
freewheel removal tool (several types around, must match your existing freewheel)
crank puller
chain breaker
allen keys

chain: http://www.ebay.co.uk/itm/KMC-Z51-6-7-8 ... 500wt_1314

crank: http://www.ebay.co.uk/itm/Suntour-XCT-V ... 500wt_1127

freewheel: http://www.tweekscycles.com/Product.do? ... 0Cassettes

The Rookie

No chain whip needed to remove a screw on freewheel!

nicklouse

but is it a cassette or a freewheel?

13-34 is likely to be a cassette.

OP read the info on Parktools to help ID what you have.

The Rookie

Agreed Nick, in which case a whip and cassette tool will be needed!

mrmonkfinger

The Beginner wrote:

No chain whip needed to remove a screw on freewheel!

doh!

cycleclinic

You need a chain wear cheaker. If the chain is worn to 0.75% or more then the chain needs changing. If the chain is worn past 1% wear then the cassette will no doubt need changing. If the the chain is between 0.75% and 1% wear then it may not. The closer it is to 0.75% wear the less likely it is that the cassette needs changing. It is sometimes difficult to tell a worn cassette by looking at it.

A worn chainset it is given away by pointy teeth. If the teeth are not pointy then then won't need changing probably.
Replacing a 7 speed cassette (shimano 13-34 is NLA) with a HG41 11-28 costs RRP of £16.99 or the HG 20 12-32Tcosts RRP £12.99. A KMC z82 chain is £9, (you can buy these parts for a bit less in some shops or on line). Fitting will take 15 minutes at the most so £75 sounds expensive to me for those jobs alone. Aso how did the second shop tell the derailier was bent. Did they really put the allignmnet guage on the bike. 7 speed bikes are not too sensitive to hanger position.

However it is difficult to tell what it is that needs attention without actually seeing the bike.