Help a Newbie!!!! - Bottom Brackets
dannloo
Posts: 15
Hi all, have been using Bike Radar for ages now as a great source of resources but now I need some specific advice.
I am a newbie when it comes to bikes and bike parts, although I just about know the names for most bits! I have been riding a lot recently for non-impact exercise after having a knee operation. I bought a Giant Escape M1 Hybrid bike in 2008 to commute to work and have been recently trying to upgrade certain components to make it more of an off road/XC bike as I now find myself riding more off road than on.
Next on my list of upgrades is the chainset and bottom bracket. Now, as a newbie to this I have been overwhelmed by all the different types of bottom brackets and crank shafts etc.
Here is a link to my bike where you can see the full spec : http://www2.giant-bicycles.com/en-gb/bikes/lifestyle/2142/31769/?collections_id=3
But the shop I bought my bike from did not install the shimano cranks listed on that page. Instead they have put on a SR Suntour PFF. I don't know if these use the cassette type bottom bracket stated in the specs.
I have seen a shimano deore chainset on ebay whith an octalink bottom bracket but I don't know if it will be suitable for my frame. How do I know what length of bottom bracket my frame needs without taking the old bottom bracket out? Can I just take a measurement of the frame and if so where?
Can you swap in an octalink bottom bracket for a cassette type one?
So many questions!!
I will probably book my bike into a local shop to have the work done as I don't have the tools required but I want to get the parts myself to save money!
The ebay item ends in a couple of days so I would appreciate any quick replies!!
I am a newbie when it comes to bikes and bike parts, although I just about know the names for most bits! I have been riding a lot recently for non-impact exercise after having a knee operation. I bought a Giant Escape M1 Hybrid bike in 2008 to commute to work and have been recently trying to upgrade certain components to make it more of an off road/XC bike as I now find myself riding more off road than on.
Next on my list of upgrades is the chainset and bottom bracket. Now, as a newbie to this I have been overwhelmed by all the different types of bottom brackets and crank shafts etc.
Here is a link to my bike where you can see the full spec : http://www2.giant-bicycles.com/en-gb/bikes/lifestyle/2142/31769/?collections_id=3
But the shop I bought my bike from did not install the shimano cranks listed on that page. Instead they have put on a SR Suntour PFF. I don't know if these use the cassette type bottom bracket stated in the specs.
I have seen a shimano deore chainset on ebay whith an octalink bottom bracket but I don't know if it will be suitable for my frame. How do I know what length of bottom bracket my frame needs without taking the old bottom bracket out? Can I just take a measurement of the frame and if so where?
Can you swap in an octalink bottom bracket for a cassette type one?
So many questions!!
I will probably book my bike into a local shop to have the work done as I don't have the tools required but I want to get the parts myself to save money!
The ebay item ends in a couple of days so I would appreciate any quick replies!!
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Comments
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Your bottom bracket will be cartridge type.
Octalink BBs are cartridge type too, the more modern stuff is external, which means youd have to have your frame faced for the external bearings to run true against.
Octalink would probably be the simpliest upgrade for yourself.
as for BB size your frame will measure either 68mm or 73mm across the width of the bb shell. The axle length is determined by the cranks/chainline.0 -
Hi AJ, thanks for your quick reply.
The bottom bracket I am looking at getting is quoted as 68mm x 118mm Spindle length.
If I go out and measure my frame in the place shown by the picture below, will I get the right measurement for the shell? Does it matter how long the axle length is if the cranks are being provided with the bottom bracket (i.e they have been used together before.)
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That is the correct measurment.
If your shell is 68 then the bottom bracket & cranks should work fine.0 -
Great thanks AJ, I have just made the measurement and it does indeed read 68mm. Thanks for helping me clear it up!0
