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-   -   Racer Tech Thread (https://www.bikeforums.net/33-road-bike-racing/956936-racer-tech-thread.html)

shovelhd 07-17-16 08:03 AM

Since number size is regulated, I'm surprised that these haven't shown up until now.

Flatballer 07-18-16 07:29 AM

I've had trouble with my rear wheel off and on since I got my Ridley Noah about 5 years ago (mostly off, since I wasn't riding). Unless the wheel is extremely true and dished perfectly, it rubs on the seatstay, and even when it is perfect, I can push the tire with my thumb and get it to touch the seatstay.

The seatstay around the tire is extremely narrow, and I'm using 23mm GP4k, which you know measure more like 25mm. This doesn't leave more than a few mm on each side of the tire. I'm using a PowerTap SL 2.4 hub in a Mavic Open Pro rim. I don't remember the lacing pattern and I don't know what spokes they are, but it's 32 spoke I think. The spokes are round, single butted I think, 2 mm. I've checked the tension and the drive side is around 100 N-m or whatever Mavic recommends. It's not built perfectly, but the spoke tensions are pretty well balanced.

Is there anything I can do, or do I just need a stiffer wheel, and/or a better hub? Is this a good excuse to get pedal or crank based power?

ancker 07-18-16 08:00 AM


Originally Posted by Flatballer (Post 18919868)
I've had trouble with my rear wheel off and on since I got my Ridley Noah about 5 years ago (mostly off, since I wasn't riding). Unless the wheel is extremely true and dished perfectly, it rubs on the seatstay, and even when it is perfect, I can push the tire with my thumb and get it to touch the seatstay.

The seatstay around the tire is extremely narrow, and I'm using 23mm GP4k, which you know measure more like 25mm. This doesn't leave more than a few mm on each side of the tire. I'm using a PowerTap SL 2.4 hub in a Mavic Open Pro rim. I don't remember the lacing pattern and I don't know what spokes they are, but it's 32 spoke I think. The spokes are round, single butted I think, 2 mm. I've checked the tension and the drive side is around 100 N-m or whatever Mavic recommends. It's not built perfectly, but the spoke tensions are pretty well balanced.

Is there anything I can do, or do I just need a stiffer wheel, and/or a better hub? Is this a good excuse to get pedal or crank based power?

I don't see how the hub has much to do with wheel clearance in the seat stays...

Maybe your spokes need higher tension, maybe your rims could be stiffer, but the hub probably has the smallest effect on side-to-side flexing a the tire. So sorry, probably not a good excuse to get a Quarq/SRM/etc. :)

Flatballer 07-18-16 08:09 AM

Well, the powertap hub has a very large flange diameter (70mm) and I'm wondering if it's not stiff enough.

I'm afraid of going to a higher tension, since I'm already big (220 lbs) I'm worried about cracking the eyelets on the rim. I suppose I could try it though. I guess increasing spoke tension is the only way to increase the stiffness of a wheel without changing spokes or rim or hub right? There's nothing else to adjust.

Is it possible it's worn out bearings in the hub allowing play or something?

ancker 07-18-16 10:26 AM


Originally Posted by Flatballer (Post 18919962)
Well, the powertap hub has a very large flange diameter (70mm) and I'm wondering if it's not stiff enough.

I'm afraid of going to a higher tension, since I'm already big (220 lbs) I'm worried about cracking the eyelets on the rim. I suppose I could try it though. I guess increasing spoke tension is the only way to increase the stiffness of a wheel without changing spokes or rim or hub right? There's nothing else to adjust.

Is it possible it's worn out bearings in the hub allowing play or something?

Just to be clear, I wasn't suggesting you increase the spoke tension above recommended levels. Just saying it is possible that low spoke tension could lead to flex. I recommend you stick to the recommended tension.

I've not heard/seen anyone say a powertap flange is more/less stiff than any other hub flange. But that doesn't mean it isn't possible.

I just replaced the bearings in one of my PT hubs and while worn bad, they didn't cause any play. They were just rough/grindy with high resistance. I don't think sealed/cartridge bearings have play when worn. (But I could be wrong.)

Harlan 07-18-16 10:30 AM

I'd say it's a bike not built around wider tires. And that tire is wide as you know. My SLC can't clear a 25mm rim even because it's slightly out of alignment. 23mm everything forever.

Flatballer 07-18-16 10:43 AM

Yeah, you might be right. Might have to choose a tire that actually measures 23mm, instead of a 23mm that measures 25mm. That's a shame because I like GP4k, and I have a lot of them. I'm also fat, and the trend is towards wider tires, not narrower.

I really don't want to buy a new frame though.

Athens80 07-18-16 10:48 AM


Originally Posted by globecanvas (Post 18912049)
...
Latex cons: ... can't be patched on the road ....

Could you elaborate about patching latex inner tubes on a ride? I've recently installed a set, for the first time. I didn't prepare for a difference in 'patchability." (I am carrying a spare, butyl, tube as the first choice, anyway.)

Harlan 07-18-16 10:52 AM

Has anyone actually successfully patched a tube on the road? Every time I've ever tried a high pressure patch it just blows off. Fat bike tubes (when I had them, tubeless now) were easy since it was all under 10psi.

TheKillerPenguin 07-18-16 10:54 AM

I have, 2x, descending Mt Diablo. They held up just fine under the braking and all that after I stopped running over all of the big sharp gravel.

furiousferret 07-18-16 10:56 AM


Originally Posted by Harlan (Post 18920437)
Has anyone actually successfully patched a tube on the road? Every time I've ever tried a high pressure patch it just blows off. Fat bike tubes (when I had them, tubeless now) were easy since it was all under 10psi.

I gave up; the failure rate was just too high; about 50%.

globecanvas 07-18-16 10:58 AM


Originally Posted by Athens80 (Post 18920426)
Could you elaborate about patching latex inner tubes on a ride?

Supposedly regular patches will work, but every time I've flatted a latex tube it has not been a patchable hole like you see on a butyl tube. The latex rips open like a balloon. I'm only speaking from my own experience.


Originally Posted by Harlan (Post 18920437)
Has anyone actually successfully patched a tube on the road?

Sure, lots of times. I don't think I've ever had a patch fail. Be sure to clean/rough up the tube before applying the patch, and don't test-inflate the tube out of the tire, it needs the pressure of the tire to hold the patch on.

hack 07-18-16 11:00 AM


Originally Posted by Harlan (Post 18920353)
I'd say it's a bike not built around wider tires. And that tire is wide as you know. My SLC can't clear a 25mm rim even because it's slightly out of alignment. 23mm everything forever.

Specialized S-Works Turbo in 24mm ... They're a bit more narrow than the GP2K 23s and are a better tire in my opinion.

Harlan 07-18-16 11:06 AM


Originally Posted by globecanvas (Post 18920462)
and don't test-inflate the tube out of the tire, it needs the pressure of the tire to hold the patch on.

This is likely the problem. I would patch them at home later on, then inflate.


Originally Posted by hack (Post 18920472)
Specialized S-Works Turbo in 24mm ... They're a bit more narrow than the GP2K 23s and are a better tire in my opinion.

Definitely going with Spec tires after I wear out the Bontys I got on sale.

My dream setup is a staggered Jet 9s, 25mm rim front with 23mm rear. Maybe I'll find that front wheel one day, or just break down and buy a set from CC to sell the back.

spectastic 07-18-16 01:18 PM

I don't patch on the road because the glue always takes some time to fully cure. I always bring 2 tubes and a couple of patches of tire boot with me.

topflightpro 07-18-16 01:20 PM

I can never find the holes in my tubes. I have to inflate them and put them in a bucket of water to see where the air is escaping.

caloso 07-18-16 01:28 PM

I've done it, but prefer not to. I'll bring a patch kit but first choice is a new tube.

Flatballer 07-18-16 01:47 PM

I carry two tubes, then a patch kit if I'm really in trouble. If I'm already down two tubes though, I'm getting desperate (and probably running out of CO2 canisters, since I only carry two).

I have had patches work in the field, but I'm probably 50/50 like [MENTION=45841]furiousferret[/MENTION].

globecanvas 07-18-16 02:32 PM

I carry a tube and a nickel sized park tool adhesive patch kit. A 2nd (or more) flat on a ride means a field patch. I've probably had to do 6? field patches and I don't think I've ever had one fail.

Tips:

Sit on the ground to change a flat, it's more relaxing than bending over and you'll be more careful.

Take your time and find the tube damage or else you're likely to be changing it again in 10 minutes. If you don't have a hand pump, work your way slowly around the tube and if you think you found the hole, blow some air into the tube with your mouth to verify. If it's not a pinch flat (snake bite), check the tire and rim at that spot (which is why you always line up the tire label with the valve hole). Just this weekend I got 2 flats. For the 2nd one it took me like 10 minutes to find the hole, but when I did I found a matching X shaped hole in the tire that was almost invisible but went all the way through. I wouldn't have known to boot it otherwise.

If you need to patch, really take the time to clean and scuff the tube. Even on the shoulder of a busy road next to a snowbank with drivers yelling at you, take your time and do it right. Don't test inflate the patched tube, install it first.

If you use a co2 and don't use the whole cartridge, leave it mounted in the nozzle because the little bit left can be very helpful if you get another flat.

carpediemracing 07-18-16 07:16 PM

Although I generally don't train outside anymore I usually carried 1 tube if I was doing my 15 mile loop. It was hot dog shaped so except for the very end I had a bunch of cut-throughs where I could get back pretty quickly.

On longer rides, or rides like out in Maine or SoCal, I'll carry 3 tubes, sometimes four.

I don't like taking the chance on a patched tube, both for the ride home and also for whatever next ride. It's not worth it to me to risk a patch failing. In the old days, when I couldn't afford tubes, I patched them, but a few of them failed after a while.

Flatballer 07-18-16 07:23 PM

First rule of flat tires, don't talk about flat tires.

Of course I hit a pothole at 40mph today. Immediate flat in the rear, that started sliding around before I could get stopped all the way. Kept it upright though.

Both front and rear are out of true again, after I just fixed the rear a few days ago. And my truing stand is still in Charlotte, and my work stand is still in Charlotte. I'm really tempted to drop it off at a shop in the morning, I dunno. Truing isn't my favorite thing, especially in a hot garage with no truing stand and using the brakes as a guide.

Also couldn't get quite as much air in the tire with my CO2 cartridge as I wanted. Not sure why. There was more left in the cartridge, but might have been lower pressure than the tire I guess.

furiousferret 07-18-16 08:05 PM

I've been on Gatorskins all year, 0 flats. Last year on GP2k's I had 2-3 a week. I still carry 2 tubes and 2 cartridges and a flat kit just in case. My commuter bag has double that (and a hand pump).

That's going to change real soon though, race wheels are coming back out.

TheKillerPenguin 07-18-16 08:15 PM

i flatted a gator a couple of weeks ago like a bosssssss. The trick is you aim for the potholes instead of going around them.

revchuck 07-18-16 08:16 PM

I ride on rural Louisiana roads and I've had one flat here this year plus one on my Tucson trip. I might have had one last year, don't rightly remember. One the year before. Y'all are a bunch of high-grade flat magnets. :) I do carry two tubes and two CO2 cartridges, though, due to having had two flats in a thirty minute period - one in each tire - three years ago.

furiousferret 07-18-16 08:40 PM


Originally Posted by TheKillerPenguin (Post 18921840)
i flatted a gator a couple of weeks ago like a bosssssss. The trick is you aim for the potholes instead of going around them.

Bravo!

The one thing that sucks about Gatorskins is getting shelled in group rides. Before complaining, you have to check every ones tires to make sure no one else is running them....

I think I'm going to run my HED Jets and GP2ks next week and see if I notice a difference. The internet says 15-25 watts (not sure if the rr test count 1 tire or both)


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