Building a Bike by a Newbie HELP!!!

[canaryjam]

Hi There
I hope someone can help me!! I am a Newbie to building a bike and I have chosen to take on the challenge, I have bought a Dawes Discovery 501 frame second hand and want to rebuild it, I have stripped off the components that were on it (Pedals, Cranks and ithe bit between the cranks sorry as I say I am new) and now have just the frame. I am after advice on 1. Are big brackets and cranks all universal diameter wise and 2. should I go for a Shimano 105 set up?

Any advise greatly appreciated!!

A bewildered Canary

 

[e-rider]

If you don't know what the bit between the cranks is called (the Bottom Bracket or BB) then building a bike is probably too much to take on. There is nothing universal on any bike unfortunately. BBs come in about 25 different sizes!

To just get an old frame and decide to build it with 105 kit - well is it just not as simple as that. Good luck anyway.

 

[canaryjam]

cheers for the speedy response,
ok i think i am gonna go do a basic bike course before i carry on!!
Cheers

Canary

 

[Jonathan M]

Hi Canary, the parts that can vary in size from bike to bike are these:

• Bottom Bracket (BB) shell - this is the tubular threaded section that holds the bearings and axle that go between the cranks. You need to know the BB shell size, usually 68mm on a road bike (can be 73mm on a MTB), and very importantly the type of threads, English, which are the commonest, or Italian, which are less common. Suggest you take the old parts to a bike shop with the BB shell measurement - this is the "depth" of the shell between the two open ends. The BB also needs to have the right axle shape, Shimano uses JIS, campag uses ISO - slightly different angles on the axle faces, you see. Axcle length can vary too, depending on frame & crank type. Always good to buy both together.
• Headset. The usual for an older bike would be 1 inch, but could be 1 1/8th inch. If the forks have a threaded section at the top then that is what you'll need, if the forks are compoletely smooth then this is an ahead set. Again, very old bikes can have some variations on the measurement of the bearing race that fits onto the fork crown.
• Seat post (saddle post). Steel frames are often 27.2mm, but there are variuations. The old seatpost should have the size stamped on it somewhere.
• Front mech clamp - depends on type of tubing, or the frame may have a brazed on boss which does away with the clamp on mech.
• Rear axle. Older bikes could be 126mm, nowadays road bikes are 130mm, MTB's 135mm. Meaure the inside faces of the rear dropouts, that is the size that you'll need.

Building abike from scratch, even as a novice, can be a really good way to learn the right mechanicing skills, and build up suitable tools for future use. I'm one of those saddos who quite likes bike maintenance as much as riding a bike!
Hope this helps!

 

[canaryjam]

Cracking reply thanks so much I am off to my local LBS for the BB measurements!! Sorry to be a bit of a dunce but my TREK has been serviced in my LBS for 3 years and cleaning is the only work I have done on it except wheel changes!! I am sooo excited about building my own road bike/hybrid I have jumped in head first and hopefully start doing my own maitanance on my racer, I have already bought a crank removal tool and BB remover.

Cheers for the advise

Canary

 

[gbb]

If you have the old components you want to replace, then you dont need to worry about getting the right bits...they'll know what to give you if you take a sample.
If you proceed, take great care to thread the crank extractor in correctly. Get it wrong and you'll strip the threads.
Replacing with 105 ?...do you mean the rear derailleur ? This is where you'll likely struggle, setting the cable tension and getting the high low settings right. It's not rocket science, but it can be difficult. Look at youtube, there's some good tutorials on there, follow them to the letter and it's not too bad. (ive been cycling and fiddling with bikes for 40 years, but never set up rear derailluers...couple of goes after watching the tutorials, no problem)

It all depends on how deep you want to go canary...most of its straight forward mechanically if you've got the right tools and you're sensible. Some of it (the gear set up), can be a headache at first.

 

[4F]

Canaryjim, have a look at this excellent site http://bicycletutor.com/

 

[02GF74]

go for it!!! it's not rocket science. if in doubt, ask questions. if buying new components, hang on to the receipts in case you need to take them back.

 

[canaryjam]

Thanks for your advice all!! I have been to my LBS and they have advised me the BB is 122.5mm, thay have been brilliant and advised me that this BB is a very bottom end shimano triple crank, and there is no chance of using a 105 set up! Thanks for your help all!!

 

[mistral]

Hi

I'd echo Jonathan M's comments

It's a great way to learn, but just to be on the safe side maybe get your friendly LBS to give your handy work a once over ... before you tackle any hills, until you feel confident, don’t want any accidents now.

Park Tools is a good resource - http://www.parktool.com/repair/

Also check out - http://sheldonbrown.com/beginners/index.html

Good luck & have fun

 

[canaryjam]

Any Ideas how i can measure the BB accurately??
Cheers

 

[Matthames]

Any Ideas how i can measure the BB accurately??
Cheers

If it were me I would measure it with a vernier caliper and note down diameter and length of body and length of crank.

Edit: it is possible to get an accurate enough measurement from a steel ruler.

 

[Dan B]

+1 for the Sheldon recommendation

 

[Norm]

I needed a new BB, so took the bike into my LBS earlier today. They asked for the old crank and took the dimensions from that. Wish I'd realised that at the time, it would have been a lot easier just taking that rather than carting the whole bike around.

 

[canaryjam]

Hi all thanks for your advice but I have bought a virtually brand new Carrera Virtuoso for 200 quid! Easier to maintain swap and replace bits!!
Cheers

Jeff