Muddy Fox Courier Comp

Day 1 of my first geared bike build. I picked up this 89 Muddy Fox Courier Comp for £40. She's seen better days but the frame has a certain charm about it I couldn't say no.

My previous builds have all been vintage road frames and fixed gear so this time I wanted something suitable for long distance/touring. The frame is the only thing I'll be using so replacing parts with new/ whatever I can get my hands on for cheap. I know mountain bike frames have different sizings to road bikes/single speeds and considering my lack of knowledge with geared bikes in general, I was hoping for some advice.

I'd like to replace the 26" wheels with 700c. Tyre clearance, brakes and wheel axle/rear drop outs width are the potential issues. Rear drop outs measure up to 130mm so 1) is it possible to find a wheel like this pre-built maybe off a hybrid bike or something? Or would I need to use a mtb free hub and lace it to a 700 rim? I tried out a 700 wheel I had lying around on the front and plenty of tyre space. Frame + fork also have the drillings for caliper brakes, if I decide to go that route.

The plan for gearing is to have a 1x drive train with a 9/10/11 speed cassette. In terms of ratios, I have a few numbers, which mean little to me but some of you will know. 2) If I were to ride something between a 40 - 46T up front and 10/42 or 11/40, does this sound viable for mostly road use? I guess something generally suitable for climbs with a decent top end on flat is what I'm after.

Next problem is bb spindle length. This one here is about 122mm, which is no use with a single chain ring, so 3) do I buy a bottom bracket and 1 ring crank set first, then decide on cassette size at the back? What are the possible issues with chain alignment (if any) in this situation?

Cheers in advance and I'll keep you posted as and when things progress

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Cool bike, I did a similar one recently.
(1) why 700c? you can get much fatter (funner) tyres on it with 26". Spacing is going to be 100 front/135mm rear which makes the rear a bit wider than road hubs at 130mm. that means you can go up to 10 speed, 11t minimum cassette cog.
(2) you should be able to get a 11-42 10sp cassette on there with not much hassle. any bigger range and it gets harder. I'd go with a 40/42t chainring up front with that cassette.
(3) normally need around a 113mm BB for a 1x setup on these old frames.

1) 130 mm rear spacing means you can chuck basically every road/trekking/gravel/whatevs wheel there, as 8 speed and above 700C wheels are usually 130 mm. Most MTBs of the era had 135, so Muddy Fox was a bit behind the curve. But yeah, going with Alban's question here, why 700C?

2) I personally use 36T/11-34T on my hybrid, and I find it almost enough for flats. But this is entirely up to your personal preferences - I am not a fast rider. I'd say 40/11-40 is a sensible choice, a 1:1 ratio for not-very-steep climbs is adequate, albeit if you plan on having a lot of luggage, you should just opt in for a compact double.

3) That's a good question. I'd say avoid integrated cranksets as they tend to push the chainline far out with these old, 68 mm BB sheels. And if you're planning to get an approximately 40T chainring, make sure it doesn't rub the chainstays, because in the standard triple crankset middle position that can be an issue. I'm building up an old MTB right now, I put a 42T to the middle - with the factory stock BB it's almost touching the stays. Just something to consider.

Generally just like the look of a larger wheel. But tbh you're right after looking into other options I think I'm either going to go with a 26" wheel or 27.5 650b wheel and run some chunky tyres on there. I didn't even know the latter existed till doing a bit of research yesterday. But it seems 650b's are hard to come by with a 130mm rear axle and rim brake. A lot of what i've seen of 650's are disk brake only with a 142mm rear axle.

Ye I think as Alban mentioned I'll probably go with either a 42/11-42 or you're suggestion of 40/11-40. Seems like that may be a nice middle ground for what I'm intending it for.

Ye I've also had similar issue's with stock bb's and upgraded cranksets. I just ordered a Shimano Deore XT BB yesterday so I'll run that with a 2 piece crankset. Also first time using this style crank, only ever previously had 3 piece square tapered. Fancied an upgrade this time. What I'm not sure about is how my chain line will be with a crank like this. Square tapered spindles have are easily measurable but what should I be looking out for measurement wise with a 2 piece set so as to not f up chain stays?

If you decide to go with 700C/650B, you’ll have to get creative with the brakes as the studs on your frame are positioned for 26” rims.

Update:

Spent the last 24 hours chemically extracting a seized seat post. The top was about 25cm down inside the seat tube to the point where you could see the end through the first bottle cage drilling. When the guy said to me "oh ye there's a stopper inside the tube so that the seat post doesn't go down too far" I have no idea why I missed that red flag. I've dealt with a seized seat post in the passed and that was a pain in the jacobs. Never have I had to use caustic soda to melt out a seat post. All a learning experience though. Fairly simple and painless, albeit messy. The paint took a bit of a beating but I'm getting this in for powder coating next week.

I've found someone over on Retrobike who does vintage decals so putting an order in for those.

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With 650B you could possibly use a few vague type of cantis, there's some in the market that has the adjustability. But yeah, calipers are usually more common with the right dimensions for the job.
However, since conversions like this are rather trending right now, you could probably get the canti bosses welded a tad higher so they'll work with 650B. I see guys on the forum regularly getting this done.

And about the BB, I really don't know. Normally I'm a measure at least 3 times guy, but this is something I always go down the trial and error route.

I’d be inclined to respace the frame to 135mm. Simple DIY job, will open up hub/wheel options massively.

There's drillings for caliper brakes on here, which would be more set up for 700's. I know you can get adapters to raise the position of v brakes to fit 700/650 and if I'm not mistaken, caliper brakes come in varying lengths and adjustable pad heights?

You recon finding a 650 at 130mm is gonna be tricky? Your probably right, I've struggled to find anything 650 with rim brakes let alone a 130mm axle

The drillings are there more as rack/guard mounts and are unlikely to line up with all but wacky specialist calipers; this frame is designed for stud-mounted brakes.

Path of least resistance for 650B would be something like Paul Motolite brakes (£££), or vintage Tektro equivalents (rare), with sliding pad mounts that can be raised enough.

Also consider that the chain stay clearance on this particular frame is quite tight.

Wow those Paul motolite brakes are £££.

I saw @Frerman build and don't particularly fancy recreating his chain stay crimping. He did seem to have fairly fat tyres on there. I guess I'll have to cross that bridge when I come to it

Easily find 26 inch wheelset with 130 mm hubs. I have a set in the garage I’d sell you if I was in the same country as you.

Trying to put 700c and making this a light fast bike doesn’t make much sense. I’d take inspiration from all the rad 26” bikes that have been appearing if I were you.

Which XT crankset did you buy? The newest version or the older double version? I wouldn’t stress too much about chain line and just stick the chainring on the inner or outer depending on which end of the cassette you will be using the most.

There's a canti brake out there that's super cheap and basically does what the Paul Motolite does. The only downside it's a total ballache to get it set up. But otherwise dreamy. Think it has a total adjustment range of about 35mm. I can check this on my pair if you want. Which could mean you might be able to squeeze a 700 in there.

I vote do what you want with it. It's your bike. Sticking skinny 700s in a 26r frame was a big thing a while back. You do you honey.

What are these cantis?

Ye I realised this one wouldn't be a fast and light when I first felt the weight of the thing :D. But I've been loving all these 26" builds they've been giving me all my ideas. I do like the bigger wheel but I think I'm slowly edging towards a 26" or 650.

Not got as far as the crankset yet, but just ordered a Deore XT bb. I'm figuring out my options now for a crankset that'll work. Am I right in thinking any 2 piece crankset will work with this bb or am I having to run specifically an XT crankset?

Any non-boost Hollowtech II cranks with a 24mm axle will work. You may have to play with the spacers that come with the BB to optimise chain line.

Canti brakes are bit ball achy in general aren't they. Ye please let me know what these brakes are and I'll check them out.

I tried the 700's off my current bike and they didn't even fit the front drop outs. Realising now that finding the right wheels is going to be a tuff one.

Check out the chinese Litepro V-Brakes on ebay. I don‘t have any 1st hand experience with them but others have used them on 700c conversions + they‘re cheap and look nice.

Top tip, bookmarked, thanks!

tbh those look way better than the cantis I spoke of.

You‘re welcome. They‘re also available in gold for the budget-minded wanker.

Lovely stuff. Kinda wish they had an all black version

I've managed to find some 26" and 27.5" rims. Can someone tell me why these are so cheap? What's that catch?

https://www.decathlon.co.uk/search?Ntt=v+brake+wheel