Finding a modern crank for my 1990 Muddy Fox Courier Mega

[scarleton]

I have a 1990 Muddy Fox Courier Mega. I returned to riding last year after being away for about 15 years and she needs some updating. Yea, I know the wise thing to do is just get a new bike, but...

Over on this side of the pond, everytime someone someone who knows anything about bikes thinks the fact that I have a Muddy Fox is rad, and I really like the darn thing, so...

I am upgrading it to what I want. So far I have changed the handle bars to drop bars with Shimano Tourney ST-A073 3 x 7-Speed STI Lever Set and put a new 7-speed cassette on it.

The next thing that needs to happen is replace the crank. Both before and after the new Shimano Tourney, I have only been really able to shift into two of the three gears at one time. I would like to put this Deore XT on my bike, but I don't know if it will work. My concern is that it says 10-speed. My thinking is that the number of speeds on the wheel don't effect the crack that much, but when it seems that different web front stores have the speed (11, 10, 9, and 8/7) as a search option, which has me thinking that it might matter.

My questions:

Q1: How do I figure out which cranks will for for me and which will not?
Q2: I plane to replace the front derailer, as well. How do I figure out which one will work?
Q3: What is the best way to learn how to do this upgrade?

 

[Splatter Paint]

Re:

Why not replace the chainrings? I bought a full set of Stronglight ones for my bike of the same year for £35 including postage: http://www.spacycles.co.uk/products.php?plid=m2b0s149p0 They don't deliver to the US but I'm sure you could get a local equivalent?

If you buy a new set of cranks you'll almost certainly need a new bottom bracket, you'll need to measure the width of the bottom bracket shell to determine the correct one and find the axle length to match the chainset. Have a browse on Sheldon Brown's site for more details: http://sheldonbrown.com/bbsize.html

Park Tools website has lots of useful 'how to' information.

SP

 

[scarleton]

Regarding the chainrings and bottom bracket

Thank you for your reply!

I am not just replacing the chainrings because I don't like how the whole crank spins when it is under load, either. It seems time to upgrade the whole thing as to get a bit smoother ride.

So... The price I was looking at was did not include the bottom bracket, that was what I was trying to figure out... I was assuming that the bottom bracket was part of the crank, but I now get that they are sold separately, or they could be sold separately.

So is my impression correct that there will be a Deore XT bottom bracket that will fit my bike, I just need to use the link you provided to identify which the correct type.

On the back of the bike, it has Exage 400LX, so I assume the bottom bracket is this one:

Exage 400LX M400 (Triple), Length: 121, Type: Square, BCD: 110/74, Note: 7-speed 1990-92

So how exactly do I find the correct replacement bottom bracket?

 

[mrgumby]

122.5mm square taper..

Didn't the courier mega have 500LX?

 

[Rampage]

Re:

Are the rings oval , is that the problem?
If so, you can fit non-oval rings on the cranks.

 

[makster]

Re:

If you replace that fantastic old bottom bracket with some modern muck that'll be creaking in 6 months, you'll regret it!

 

[scarleton]

Re: fantastic old bottom bracket

If you replace that fantastic old bottom bracket with some modern muck that'll be creaking in 6 months, you'll regret it!

My friend, would you mind speaking a bit more into this? What is so fantastic about my old bottom bracket? What is so bad about the new stuff? Is there some incompatibility between the old and the new?

 

[scarleton]

Re: oval rings

Are the rings oval , is that the problem?
If so, you can fit non-oval rings on the cranks.

I am so sorry, but I don't have a clue as to what exactly you are referring to. Might there be a picture out there you could reference so I can get a visual?

 

[Rampage]

Re: oval rings

Are the rings oval , is that the problem?
If so, you can fit non-oval rings on the cranks.

I am so sorry, but I don't have a clue as to what exactly you are referring to. Might there be a picture out there you could reference so I can get a visual?

http://sheldonbrown.com/biopace.html

 

[makster]

Re: fantastic old bottom bracket

If you replace that fantastic old bottom bracket with some modern muck that'll be creaking in 6 months, you'll regret it!

My friend, would you mind speaking a bit more into this? What is so fantastic about my old bottom bracket? What is so bad about the new stuff? Is there some incompatibility between the old and the new?

Your actual bottom bracket may not be all that, but the a good square taper BB is so much more reliable than anything else I've used.
So much so that I'll be fitting one to a 29er frame that I've just built myself... viewtopic.php?f=41&t=297169