Author Topic: MTB conversion to Disc Road bike  (Read 4270 times)

SportingGoods

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Re: MTB conversion to Disc Road bike
« Reply #45 on: March 25, 2017, 04:56:30 PM »
I did a carbon wheel test ride today. Amazing, really  :o

- Good grip: weather was bad, pouring rain, but the narrow 23 mm tubular demonstrated a good grip. No hairpin turn today, but I never felt unsecured when crossing "swimming-pools".
- Supreme comfort: comfort was very similar to my 28 mm tubeless tires, which is a real reference in term of comfort. I still might give a try to 25 mm tubulars when I need to change but there is nothing more I really need. You really need poor roads to feel a need for better then that.
- Weight: I was not ready to feel such a difference, I haven't tackled a large climb today but the small climb I took felt surprisingly easy. And acceleration was a pure pleasure. I also found that it makes easier to maintain a sustained effort too (probably because you don't waste energy in the acceleration phase - you don't have that energy drain before the sustained effort). And note that my reference is not too bad, winter wheelset is 1.68kg with the best tubeless tires.

So, it's a big success. Next is longer, steeper climbs and it's associated descent (fast, hairpin turns) but I need to build confidence in the wheels first, I mean for the descent.

carbonazza

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Re: MTB conversion to Disc Road bike
« Reply #46 on: March 27, 2017, 04:07:25 AM »
I did a carbon wheel test ride today. Amazing, really  :o

I though you had already carbon wheels on it. I guess you built them yourself  :)
Do you mind to give some details: which spokes, hubs, rim size and final weight?
Something special for tubulars, and impressions vs. tubeless?

SportingGoods

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Re: MTB conversion to Disc Road bike
« Reply #47 on: March 27, 2017, 08:38:38 AM »
Well, I had most of the components for a long time (except the spokes) but I had to wait for my MTB wheels to be build to free the hub! Till then I was using ZTR Crest rims on XT hubs (my former 29" wheels). Those are good wheels, below 1.7 kg. I've been using those all through the winter with Schwalbe Pro One tubeless tires, 28 mm. It makes a really good set of wheels. On winter dirty, slippy roads, they've been fantastic.

Now the Carbon wheels  :)
- Rims: carbon, 30 mm deep, 23 mm wide, specific for tubular (a lot lighter then for tires). 300g each. From Peter who made them special for me w/o brake surface, all shiny, so beautiful! Very affordable product!
http://www.xmcarbonspeed.com/Productinfo.asp?f=1470
- Hubs: Novatec D711/712SB. Those are the hubs that were mounted on the 27.5+ wheels I bought from Peter. Cost is zero!
- Spokes: I gave a try to flat spokes, CX-Ray. They are expensive, even though Peter got a good price for me (more expensive then the rims...). I don't regret it, they are very light and look nice.
Overall, 604g front, 737g rear. It could be lighter with fewer spokes but my hubs were 32 holes, I thought it would be stupid to buy new hubs just to reduce spoke counts. But if you pick 28/24 combo you can save another 40-50g.

Tubulars are Vittoria Corsa CX III, 23 mm. I was a bit worried to get down from 28 mm to 23, but I have no regret so far. I wanted these wheels to be as light as reasonably possible but they also prove to be of very similar comfort to tubeless 28 mm (a lot better then regular tire/tube). Gluing process is scary at first, but honestly there is nothing difficult. I carry a light and compact tubular in my saddle bag, in case the latex doesn't work. Changing the tubular is actually faster then putting a tube in my tubeless wheel.

As you might have seen on Strava, I got more confidence today and topped 71 km/h in a descent, but I was very careful, light on the brakes, paying attention to any suspect noise. And I trust that these nice wheels made my climb a bit less painful. 10%, 10 km climb :'(

carbonazza

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Re: MTB conversion to Disc Road bike
« Reply #48 on: March 28, 2017, 03:59:11 AM »
Thank you for sharing the details.
It intrigues me now, I could go too for tubulars instead of tubeless too.

You are putting sealant in them right?
Do you see already the fat/wet spots(plugged holes) we see on our MTB tires when they dry?

Since there are many roads with cobbles here, that hurt hard, I would have liked a 25 or 28mm instead.
Was it for the weight you took 23mm?

I reached my record too this weekend at 70Km/h, but the bar started all of a sudden to shake strangely, and I thought I was going crash hard.
The same evening I was still feeling that bad impression :o

SportingGoods

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Re: MTB conversion to Disc Road bike
« Reply #49 on: March 28, 2017, 04:27:16 AM »
It's a tough call for you... I would pick 28 mm for Northern France/Belgium. Not sure tubeless or tubular (both are good options). The reason I selected tubular for my carbon wheels is really because I wanted a very light set of wheels, for the nice season, for the mountain (with 60 minutes climbs). Tubular themselves are not lighter then tubeless tires but the rims are. My rims are 300g, tubeless/clincher rims are closer to 400-420g.
I selected 23 mm tubular because they provide good comfort and light weight, but I'll try 25 mm tubular next (with a 20-30g/tubular weight penalty) for even greater comfort.

If you think about repair/setup pain, I think tubular is better. I have some latex in my tubular so I should be good for small punctures. Replacing a tubular on the road is fairly easy. The only pain is that it takes several days to put a tubular on when the rims are new (then just 24 hours of drying time when you replace a new tubular). Tubeless are as easy for small punctures, but they are a big pain when sealant doesn't work. Tubeless tires are difficult to mount, potentially impossible when stressed, under the rain, frozen, on the side of a dirty road. I don't want to face the day when sealant doesn't work on my road bike or MTB (I have used "m├Ęches" once successfully though, no need to demount the tire). Removing and replacing a tubeless tire is one big pain.

PS: I agree that past 70 km/h is scary. It requires full focus on what's going on. My bike was still very stable at that speed and that's because it's a MTB frame, with a longer wheel base. The phenomenon you mention is called "guidonnage" in French. You can Google this key word for advices to fix the problem.

tripleDot

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Re: MTB conversion to Disc Road bike
« Reply #50 on: March 28, 2017, 01:44:58 PM »
About 16 or 17 years ago when I got my first trail worthy HT XC for only a couple of months, I hit 70kph going downhill (road).  It was such a rush and exciting I might add.  It didn't scared me.  I actually loved it.  Even talked about it for a few days.  But it got me thinking hard and eventually got myself on a self-imposed speed limit.  No over 40kph downhill and no over 55kph on flat.  I still abide by this rule to this day although I do get tempted to break the downhill limit once in a while.  Reason for this speed limit... I always knew my strenght was endurance riding not speed, not agility and not concentration, my simple goal was to be able to keep on enjoying cycling way past retirement age.  Be safe.

SportingGoods

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Re: MTB conversion to Disc Road bike
« Reply #51 on: March 31, 2017, 08:24:32 AM »
OK, I found the limit of 23 mm tires: cobblestone. I had crossed railways, it was fine (modern ones, as flat as can be). But I've tried a short section on cobblestone this week, at a descent speed. No good. I couldn't do that for extended time. 28 mm tires was way better on the same section.
It interesting that I can only tell a real difference on such a difficult road. All the railways, potholes, speed bumps felt about the same with 23 and 28 mm tires.

So, Carbonazza, it suggests that 23 mm is a no-go for you. You want either a very comfortable 25 mm tire or 27/28 mm.

carbonazza

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Re: MTB conversion to Disc Road bike
« Reply #52 on: March 31, 2017, 10:28:30 AM »
So, Carbonazza, it suggests that 23 mm is a no-go for you.

I should expect some pain at the tour of Flanders tomorrow then  :o