Disc only on the front, any good??

[kawa9999]

Hi,
we currently brake on v Brakes on front and rear on our steel tourers. So far actually quite ok.
As we are planning a longer tour, couple of years, we are checking to have new wheels built as we want to mount some wider tyres. So in parallel I was thinking of maybe building a disc wheel for the front, and swapping the fork. Currently we have a Surly LHT fork, I would need to get a Disc trucker Fork. That would not change the geometry of the frame, same fork just with disc mounts.
We are not much concerned about stopping power, which so far seems ok (even if we did not yet had the chance to test going down an alpine pass in pouring rain) but more on the rims getting grinded. Discs seems to solve this issue at least partially.
So does it make sense to put disc only on the front?
Furthermore:
- Do you think it is a good idea putting a v-brake enabled rim on the front also (even if we would have discs)? Thinking of the old story, just in case you need it swapping the front rim (unused as having disc) if the rear one gets too much used.
- We have a custom rear wheel currently, novatec hubs with 130 mm OLD, sapim strong and ambrosio rims. They work pretty well, but we would need to change the rims to mount pretty wider tyres (which we already tested would fit fine in the frame). Now, we are actually pretty happy with the novatec hub. It has sealed bearings and works smothly also after many kms. But it is 32 holes. Do you think it makes sense to swap it for a 36 holes one?? Does the 4 additional spokes make a difference?? We indeed want the strongest possible wheel, but I am not sure if 32 vs 36 does not make much of difference. We do not want to go up to 40 spokes, that start to be too exotic.
-Any suggestion on a relatively cheap, 36 holes hub, with sealed bearings? We had some shimano, but really prefer the sealed bearings, they work much better for us.
- As we have a steel frame with 130 mm OLD on the back wheel, do you think it make sense to widen it to 136 OLD so we can use MTB hubs?? I have seen somewhere that the wider the hubs, the stronger the weheel. We could have one experienced guy to do this for sure, I think he knows what he does, he used to be the official Pinarello on the road mechanic in tour de France and Giro. So I think we can trust him.
Thanks and wish you good rides from Italy.
manuel

[Si]

Were you intending to use hydraulic or cable? If it was me I'd go for cable and use a fork with the canti mounts still on it (with bolts in so that they don't stab anything/one in a crash). That way if the disc fails you can move the rear V brake to the front and attach it to the correct brake lever (or just carry a spare V). Likewise a cable disc will be easier to keep going than a hydraulic.

[kawa9999]

Definitely going with cable discs, as I have dropbars. Probably Avid BB5 or BB7 with tektro V Brake specific levers.
I also thought about a disc and V brake fork, but seems quite difficult to get one. Looking for steel fork, with a similar rake as the surly LHT, I have tried straight forks and seems much rougher than the bended ones. Oh and for 28 inches wheel.
Any suggestion on the model??

[meic]

As for the rim, certainly fit a rim brake type one, almost nothing is lost by doing that and it means you stand a better chance of rigging up an alternative front brake as well as the obvious advantage you can swap it to the rear.

It may be that you just damage your rear rim and discs work better with damaged rims than V brakes do, though I am not sure if it is worth doing a rim swap in the middle of the desert/ jungle/outback etc.

For the same reason you will probably want the same spoke count front and rear if you do buy a new rear wheel.

I use a disc brake just on the rear as, amongst other reasons, I drag a lot on the rear brake and wear out rims quite quickly doing it. The disc was a disappointment in that it seems to overheat quicker than the rim brakes did.

I would be worried about anything which increases your spares list. If you have different sets of brakes front and rear, you need two sets of spares and possibly tools.

On that point unless you are carrying a proper cassette tool make sure you use a 6 bolt disc rather than a Centre-lock.

[Si]

The disc was a disappointment in that it seems to overheat quicker than the rim brakes did.

A fair bit was written about this a while back with people like Santana doing tests ad finding similar. A lot of it seems to be down to the disc that you choose. My Hope mini is a git for heat failure, but by replacing one of the internal parts such that the heat transfer is rerouted much of the trouble is removed.

[Barrenfluffit]

If you need to use rim brakes you'd also need to be using suitable wheels; probably not a problem but a consideration. I reckon that big disks are a better bet for shedding heat and the front is where most of the hard work is done. BB7's are pretty simple; not many moving parts at all.

[simonhill]

If you are worried about wearing out your rims, then surely a rear disc is more appropriate. Maybe I am unusual, but I wear out my rear rims and brake pads far quicker than my front.

Your other post is worried about using 700s in Asia, why complicate it further with non standard up-grades to your forks and brakes?

[andrew_s]

Note that a tyre fitted to a wide rim measures a little wider when fitted to a wide rim that it does when fitted to a narrow rim, so if your check showed a small clearance you could have a problem fitting the desired tyre.

Cable disc/brake lever:
If you use V-brake compatible levers, you should use the black MTB version of the BB7 (as I expect you know, but just in case).

Front/rear rim wear with rim brakes is very variable - some people wear the front rim faster, others wear the rear rim faster. The front does more work, but the rear is often working in a dirtier environment (i.e spray off the front), resulting in more grit in the pads.

[kawa9999]

Hi Simon,
yes you are right, amd yes the two questions are related, but my frame does not allow disc on rear, and for that I would need to change the whole bike. Putting it on the front would mean getting a new fork (actually exaclty the same identical Long haul trucker fork I have, just the one with disc mounts) and 1 new front brake. The question was more, is it worth at all to just put it on the front? I need anyway to get new wheels (need wider rims).
The second idea was that in weird situations (pouring rain big descent), having 1 working brake is better than having none.
I have no idea about availability of disc replacement in asia, my assumption is/was that the probability to need some (except pads and maybe 1 rotor which are small and I can carry anyway) is almost to zero regarding mechanical disc brakes.
Regarding weight, we have 2 identical bikes, so carring spares would be the same as having one complete disc bike and one complete v brake bike.

[meic]

The second idea was that in weird situations (pouring rain big descent), having 1 working brake is better than having none.

Doesnt have to be a descent, having even one disc brake makes a lot of difference in the wet, the only reason I have kept mine.

Regarding weight, we have 2 identical bikes, so carring spares would be the same as having one complete disc bike and one complete v brake bike.

Except that when traveling in a pair you would be expecting to halve the number of spares you each have to carry.