carbon wheel stiffness vs weight; racing on clinchers

Back by popular demand, the general all-things Road forum!

Moderator: robbosmans

spectastic
Posts: 35
Joined: Wed Jun 24, 2015 8:11 am

by spectastic

greetings fellow bike nerds,

I made this account because I have two questions that I feel like people on here would be familiar with.

1. I'm contemplating on selling my 50x23mm tubulars for clinchers. the reason for the switch is because I don't want to train on tubulars, and so my good racing wheels only see action once every couple of months, and that sucks. the latest clinchers are pretty close to tubulars, and the weight penalty is only around 100g per wheel (wheels and tires) for the particular clinchers I'm looking at. would people agree that 200g of extra rotational inertia is insignificant in a field sprint effort?


2. the wheels I'm seeking to buy are from a chinese manufacturer, which lets me pick the spokes. I get to pick light spokes, or heavy spokes. I assume the heavier spokes are stiffer, yet the lighter spokes will save about 100g per wheel. Which one is the marginally wiser decision, and why? On the same note, a 50x25 rear wheel is stiffer, but heavier than a 38x25 rear wheel. the aerodynamics of a rear wheel is trivial, so again, if you were to pick between the two, which one would you take, and why?

thanks


PS. I don't know how much power I generate, but I'm a 165 lb cat 3 who does well in field sprints, just to give you an idea.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



victorduraace
Posts: 230
Joined: Thu Jul 14, 2011 10:10 pm

by victorduraace

why not train on tubs? pick some rear conti sprinter/ tufo s33 and pour some sealant, perfect mile-clocking setup, get decent tubular up front and just ride...

Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

I ride 3 sets of Chinese clinchers (Farsports), and I weigh around 170lbs. I can put out a decent amount of power and do ok in sprints.

Set 1: 50x23, 20/24 spokes, rear 8:16 lacing, Edhub, 1330g, all light spokes. All good after 5000k, just swapped out the bearings.
Set 2: 24x23, 20/24 spokes, rear 12:12 lacing, Edhub, 1220g, rear drive side has heavier spokes. 1 spoke broke after 700k.
Set 3: 38x26, 20/24 spokes, rear 12:12 lacing, Novatec hubs, 1535g, rear drive side has heavier spokes. New, got them last week. Universal set for commuting, road & gravel.

My thoughts:
- Wide rims are heavier. If I had to pick only 1 set, I'd go for my 50x23s, or have a mid-weight 38x23 set built.
- Edhubs (Bitex RAR9) are slightly flimsy, but if you don't use them with MTB gearing or on gravel when you are at off-season weight (I did all 3), they'll be fine.
- My 24x23 are more than stiff enough. The 50s are a maybe slightly less stiff laterally because of the 2:1 lacing.
- Wide, U-shaped wheels do much better in crosswinds. However, on a really windy day I'd still rather go out on the 50s than the 24s if it was a fast ride. I'd just be more careful when taking a sip from the bottle etc.

200g of rotational inertia won't slow you any more than 200ml more in your water bottle. This has been proven many times. Still, 200g is 0.2kg. Steering might feel slightly different with a 100g heavier wheel.

My suggestion: Go for a 38x25 or 38x23 set with 20/24 spokes, 2:1 lacing with all light spokes. Select rim width depending on which tire width you want to run. I'm running 23mm front /24mm rear on my 50x23 set.

If you want to ride in the hills, make sure the rim has high-temperature resin in the brake track.

bm0p700f
in the industry
Posts: 5777
Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
Contact:

by bm0p700f

I have a set of 25mm wide 50mm deep clinchers laced to Miche hubs. I did them myself. 7500km of mixed weather riding and the hubs and the rims simply wont wear out. I would love to rebuild with a tubular rim for training and racing but I can't justify it.

I would be pretty disapointed with a spoke breaking after 7000km but then again spoke life is only as good as the quality of the wheel build.

I would keep what you have and fit some conti tubs pour some sealant in and ride. The weight saving will allow you to carry a spare tub in your back pocket for added piece of mind.

spectastic
Posts: 35
Joined: Wed Jun 24, 2015 8:11 am

by spectastic

Marin wrote:I ride 3 sets of Chinese clinchers (Farsports), and I weigh around 170lbs. I can put out a decent amount of power and do ok in sprints.

Set 1: 50x23, 20/24 spokes, rear 8:16 lacing, Edhub, 1330g, all light spokes. All good after 5000k, just swapped out the bearings.
Set 2: 24x23, 20/24 spokes, rear 12:12 lacing, Edhub, 1220g, rear drive side has heavier spokes. 1 spoke broke after 700k.
Set 3: 38x26, 20/24 spokes, rear 12:12 lacing, Novatec hubs, 1535g, rear drive side has heavier spokes. New, got them last week. Universal set for commuting, road & gravel.

My thoughts:
- Wide rims are heavier. If I had to pick only 1 set, I'd go for my 50x23s, or have a mid-weight 38x23 set built.
- Edhubs (Bitex RAR9) are slightly flimsy, but if you don't use them with MTB gearing or on gravel when you are at off-season weight (I did all 3), they'll be fine.
- My 24x23 are more than stiff enough. The 50s are a maybe slightly less stiff laterally because of the 2:1 lacing.
- Wide, U-shaped wheels do much better in crosswinds. However, on a really windy day I'd still rather go out on the 50s than the 24s if it was a fast ride. I'd just be more careful when taking a sip from the bottle etc.

200g of rotational inertia won't slow you any more than 200ml more in your water bottle. This has been proven many times. Still, 200g is 0.2kg. Steering might feel slightly different with a 100g heavier wheel.

My suggestion: Go for a 38x25 or 38x23 set with 20/24 spokes, 2:1 lacing with all light spokes. Select rim width depending on which tire width you want to run. I'm running 23mm front /24mm rear on my 50x23 set.

If you want to ride in the hills, make sure the rim has high-temperature resin in the brake track.


shouldn't all rims have high temp resin, not just in the brake track, but EVERYWHERE?

that does remind me of another point. clincher wheels have quite a bit of pressure being exerted on the walls, constantly. does this affect the life span of the wheel significantly compared to a tubular?

Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

No need to have hi temp resin elsewhere, and it's expensive. Tubulars will fare better if you overheat them, but if you don't, the life span will be the same - they'll probably last forever.

spectastic
Posts: 35
Joined: Wed Jun 24, 2015 8:11 am

by spectastic

I had kind of a scare in today's training crit. right after the finish, a guy bumped me off the road, and the gravel was bad enough that it gave me a huge pinch flat. good thing I had ksyrium elites, which are super strong. it makes me wonder whether a carbon wheel would be able to handle an abuse like that, considering carbon fiber has relatively low impact strength compared to aluminum. maybe I'll just get the heavier spokes just to have a stronger wheel

phollingswo
Posts: 77
Joined: Mon Feb 02, 2015 12:40 pm

by phollingswo

spectastic wrote:I had kind of a scare in today's training crit. right after the finish, a guy bumped me off the road, and the gravel was bad enough that it gave me a huge pinch flat. good thing I had ksyrium elites, which are super strong. it makes me wonder whether a carbon wheel would be able to handle an abuse like that, considering carbon fiber has relatively low impact strength compared to aluminum. maybe I'll just get the heavier spokes just to have a stronger wheel


Carbon wheels are pretty damn tough to be honest. A lot of riders use them for cross, which doesn't suggest they were worried about strength!

Also look at the Martyn Ashton Road Bike Party videos - all done with carbon wheelsets.

spectastic
Posts: 35
Joined: Wed Jun 24, 2015 8:11 am

by spectastic

phollingswo wrote:
spectastic wrote:I had kind of a scare in today's training crit. right after the finish, a guy bumped me off the road, and the gravel was bad enough that it gave me a huge pinch flat. good thing I had ksyrium elites, which are super strong. it makes me wonder whether a carbon wheel would be able to handle an abuse like that, considering carbon fiber has relatively low impact strength compared to aluminum. maybe I'll just get the heavier spokes just to have a stronger wheel


Carbon wheels are pretty damn tough to be honest. A lot of riders use them for cross, which doesn't suggest they were worried about strength!

Also look at the Martyn Ashton Road Bike Party videos - all done with carbon wheelsets.


oh yea good point. the freestyling did some serious numbers on that bikes.

shaolin
Posts: 32
Joined: Wed Jun 03, 2015 7:08 am
Location: Shanghai, PRC

by shaolin

My carbon rims (front to be precise) survived attack of a scooter (guy cut me off at the junction in Shanghai and I hit him in the middle of his machine of death). Result = two broken spokes and scratched decals, rim went out of true of course. After replacing spokes it was like a new.

spectastic
Posts: 35
Joined: Wed Jun 24, 2015 8:11 am

by spectastic

shaolin wrote:My carbon rims (front to be precise) survived attack of a scooter (guy cut me off at the junction in Shanghai and I hit him in the middle of his machine of death). Result = two broken spokes and scratched decals, rim went out of true of course. After replacing spokes it was like a new.


how is cycling in shanghai? they're addressing the pollution problem last i heard. how is cycling in china in general?

shaolin
Posts: 32
Joined: Wed Jun 03, 2015 7:08 am
Location: Shanghai, PRC

by shaolin

In Shanghai we have three problems:
1. Pollution, avg is 150-160, which is still ok for cycling but we have days where AQI goes above 200 or even 300... Above 200 mask is very useful, above 250-300 better stay at home (and buy air purifier). But Beijing for example is much worse...
2. Other road users... All drivers and riders should get a prize for creative driving... I am from Poland so I am used to strange situations on road but here is a completely different level... :wink: still better than other Asian places...
3. Shanghai is flat like a table. First proper climbing is at least 2h drive from the city...

Other than that we are quite happy. Roads are very good, lots of great road bikers, we ride mostly during weekends (we start 6:30am and do 100-200km on Sat and 70-100 on Sunday, both sides of the river have their own groups so everyone can find something that suits him best). Also some rides during weekdays. Two proper racing series (Shanghai Classics and Shanghai Heros). And more...

More info at our newly developed website - http://www.shanghaicycling.org - it should give some idea (especially Gallery) about riding here.

And riding in China is an epic experience... Hard to describe in few sentences. Best would be to come here and just do it!

sawyer
Posts: 4485
Joined: Fri Dec 15, 2006 7:45 pm
Location: Natovi Landing

by sawyer

@shaolin - how popular is road riding in Shanghai and is it growing?
----------------------------------------
Stiff, Light, Aero - Pick Three!! :thumbup:

spectastic
Posts: 35
Joined: Wed Jun 24, 2015 8:11 am

by spectastic

I'd like to back on the high temp resin on the brake track for a second. Is this to suggest that some carbon wheels DON't have this on their brake tracks? one of my concerns with carbon clinchers is the walls buckling on me. I think the main cause of that is excessive use of the brakes on a steep descent. I also think there are some stories where the walls buckled while changing a tire.

Can someone elaborate on this issue, the causes, risks, etc?

shaolin
Posts: 32
Joined: Wed Jun 03, 2015 7:08 am
Location: Shanghai, PRC

by shaolin

sawyer wrote:@shaolin - how popular is road riding in Shanghai and is it growing?


Depends on how we want to measure it. Up to 100ppl riding every weekend on both sides of the river. Biggest race this year was 500-600ppl in total. But if you compare it to the population of the city this is nothing. Chinese treat cycling as a way of transport, not as a way of living... If you want to know more write me a PM as I don't want to be kicked out for offtopic :wink: :wink:

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



Post Reply