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-   -   Wheels and tyres for 200km mountainous audax (http://www.bikeforums.net/long-distance-competition-ultracycling-randonneuring-endurance-cycling/843736-wheels-tyres-200km-mountainous-audax.html)

stevage 09-03-12 12:04 AM

Wheels and tyres for 200km mountainous audax
 
Hi all,
I'm considering entering the (Australian) Alpine Classic in January next year. 200km, some 2000m+ of climbing. I use a Specialized Tricross Sport for virtually all my cycling, with 32 or 35mm tyres.

Two questions I have:
1) Given that most of the ride (timewise) will be spent climbing, is there much advantage to skinny (23mm) tyres? Or is the comfort of wider tyres more important?
2) Given that most of the ride is spent climbing, is it worth trying to get lighter wheels?

I think the most of the other people doing the ride will be using super lightweight road bikes, but I think I'm better off sticking to a comfortable bike I'm used to. Agreed?

(For a bit of context, I've done lots of cycle touring, but few days of more than 120km. Once did back-to-back 165km days, on borrowed road wheels and tyres, but that was pretty flat, in a peloton. Yes, I'm planning on training :))

Homeyba 09-03-12 08:33 AM

Lighter tires and wheels will have a benefit climbing. Whether it's worth it to you or not I don't know. There will be a ride quality trade off. If you're getting the wheels and tires loaned to you for free, why not. You'll definitely feel the difference but it won't save you large quantities of time.

Commodus 09-03-12 10:12 AM

Time saved will be so minimal, I wouldn't bother, personally.

I like my big comfy tires, and value the comfort more than the handful of minutes I would save with lighter wheels.

If you really want to push the pace, lighter equipment starts to be more important...but given this your first 200, I'm guessing that doesn't apply to you.

DaHaMac 09-03-12 11:03 AM

Rotational Weight is felt more than any other weight, except maybe that around our waist imho. Having said that, I wouldn't be worried about switching bikes unless you are just looking for a reason to justify n+1. However, you could save a lot of rotational weight by switching to a lighter tire and tube combo.

When the Vittoria Randonneur Cross tires wear out on my touring bike I'll be switching to the Vittoria Randonneur Hyper. There should be a decent weight savings of ~250g and the smoother tread on the hyper will be nice. A fellow commuter at work reliably claims to have ridden his Hypers for 4,300 miles (6935km) before have to change out the tire.

Therefore, agreeing with Commodus, if you aren't trying to push the pace and want to enjoy the ride then stay with your current bike and I'd add reduce the weight of your tires without reducing the width or size of your tires by much.

stevage 09-03-12 07:20 PM

One thing I should have mentioned - the only reason I'm at all concerned about weight etc is to make sure I beat the maximum time (13 hours I think). Other than that, I'm not at all fussed what time I do. (I did a 100km mountain biking event earlier this year and failed to make the cut-off, so ended up completing only 87km. Kind of anti-climactic...)

Quote:

When the Vittoria Randonneur Cross tires wear out on my touring bike I'll be switching to the Vittoria Randonneur Hyper. There should be a decent weight savings of ~250g and the smoother tread on the hyper will be nice. A fellow commuter at work reliably claims to have ridden his Hypers for 4,300 miles (6935km) before have to change out the tire.
Lighter *and* longer lasting? I ride Randonneur Cross (and/or Cross Pros), and generally like them. My last rear tyre wore out without ever having had a puncture - but not all that many k's (maybe 2-3000). Pretty cheap though. Nice tip about the Hypers - but I note the difference between the Cross Pro and Hyper is only 80g/tyre.

mander 09-03-12 09:11 PM

If you miss the time cut on this ride it won't be because your wheels were too heavy or because your tires werent cushy enough. these things make a difference but not the hours and hours difference it will take to fill thirteen hours on a 200k.

I would just focus on getting your mind and body prepared, as well as what imo would be more significant aspects of bike preparation. Think about how you will manage nutrition, hydration and what to pack. And spend some time thinking about how you can minimize time at stops.

we all like to "upgrade" our bikes and it can certainly save you a bit of time, but right now there is so much more time you can gain by learning this basic management stuff.


Good luck! and have a fun ride.

stevage 09-04-12 02:53 AM

Quote:

Originally Posted by mander (Post 14688135)
If you miss the time cut on this ride it won't be because your wheels were too heavy or because your tires werent cushy enough. these things make a difference but not the hours and hours difference it will take to fill thirteen hours on a 200k.

I would just focus on getting your mind and body prepared, as well as what imo would be more significant aspects of bike preparation. Think about how you will manage nutrition, hydration and what to pack. And spend some time thinking about how you can minimize time at stops.

we all like to "upgrade" our bikes and it can certainly save you a bit of time, but right now there is so much more time you can gain by learning this basic management stuff.

Yeah, thanks - will definitely be thinking quite a lot about that. I'll be getting into serious training in mid November (overseas trip first). Carrying food and water is pretty easy, as I have custom made frame bag and gas tank (Epic Designs aka Revelate). Shorter stops is a good one - I spent way too long at stops during the mtb enduro.

Hydration is a big problem for me - I seem to require a lot more water than most other people. At that time of year, I could comfortably get through 2L per hour, if I remember to.

Could you elaborate on "getting your mind prepared"? Any good readings? Is there something specific to work on?

Thanks,
Steve

lhbernhardt 09-04-12 02:28 PM

The advantage of having lighter wheels is psychological, and it's a two-edged sword.

On the one hand, you'll likely climb faster just because you think you can climb faster, or you're supposed to be going faster up the climbs because you've got these super wheels.

On the other hand, if you happen to NOT make the time cut with this expensive technology, you will probably feel even worse than if you had done it on heavier/fatter wheels/tires.

Use your existing equipment. If you miss the cut by 5 or 10 minutes, then you can blame it on the equipment, and swear to come back next year with the lighter wheels. At least you'll have a positive story to tell.

IMHO, equipment is insignificant. Nobody needs the carbon fiber Di2-equipped racing bike with the carbon wheels unless they're racing a Grand Tour. For anyone else, it's all for show, and it just makes the guys n the steel bikes with the fat tires feel better about themselves when they drop you on the climbs. Besides, you could have the fanciest bike/wheels on the ride, and most people either won't care or won't know what it is, so "for show" isn't even a valid reason!

Luis

mander 09-05-12 01:21 PM

Quote:

Originally Posted by stevage (Post 14688711)
Yeah, thanks - will definitely be thinking quite a lot about that. I'll be getting into serious training in mid November (overseas trip first). Carrying food and water is pretty easy, as I have custom made frame bag and gas tank (Epic Designs aka Revelate). Shorter stops is a good one - I spent way too long at stops during the mtb enduro.

Hydration is a big problem for me - I seem to require a lot more water than most other people. At that time of year, I could comfortably get through 2L per hour, if I remember to.

Could you elaborate on "getting your mind prepared"? Any good readings? Is there something specific to work on?

Thanks,
Steve

Heh, i didn't mean anything too zen or mysterious... just start thinking about all the strategy stuff l mentioned.

Stop times can be huge. skipping a 15 min. break or taking 2 mins instead translates into a lot of extra distance. I find riding with faster randonneurs I'm often "that guy" still rummaging around in his bag when everyone else is on the bike ready to leave... part of the skill set is fast pit stops.

it's a good idea to think about food you can eat on the bike and easily carry with you. If you're carrying everything you will need (not hard for a 300) you will save time foraging at stops... you can just fill your bottles and go.

Not going too fast helps keep stop times short... if you go too hard, then feel ****ty and spend a long time drinking chocolate milk and stretching at a stop, that can be a big net loss for time.


the holy grail is a pace that you could hypothetically maintain forever. over time you get better at sensing when you're on this magic pace, when you could stand to go faster or when you should slow down.

And, make sure your bike will not get any "stupid mechanicals", i.e. stuff you could easily prevent by doing a little maintenance during the week leading up to the ride.

Those Revelate bags are great!

Chris_W 09-05-12 01:50 PM

Quote:

Originally Posted by DaHaMac (Post 14686257)
Rotational Weight is felt more than any other weight, except maybe that around our waist imho. Having said that, I wouldn't be worried about switching bikes unless you are just looking for a reason to justify n+1. However, you could save a lot of rotational weight by switching to a lighter tire and tube combo.

When climbing uphill at a constant speed, rotating weight is equally important as non-rotating weight. It is only when accelerating and decelerating that it makes a difference whether the weight is in a rotating part or not (and even then I think the difference is over-emphasized).

Even so, for my race bike I have some lighter, mountain-climbing wheels (Dura Ace 7850 C24) and some regular training wheels (handbuilt by myself, 105 hubs laced to DT Swiss RR465 rims). I also have a TriCross bike that I use for go-anywhere type rides and some touring, on which I have some heavier-duty wheels (also self-built, XTR rear hub, XT dynamo front hub and Mavic A719 rims). When I've used that bike for a few mountainous rides on paved roads, I've occasionally switched the wheels out to a lighter pair, but the difference in feel is really pretty minimal (despite the quite significant loss of weight due to losing the dynamo hub).

Even on the go-anywhere/touring wheels, I normally only ride a 26 to 28 mm front tire and 28 to 30 mm rear tire - that feels pretty plush to me and pyschologically I feel so held back when riding anything wider than that (although in reality it probably isn't having much affect). I occasionally ride sections of MTB singletrail with my 26 mm front, 28 mm rear combintation (as I said, this is my go-anywhere bike), and I can do that without too much trouble, so I can't see the point of anything wider.

mander 09-05-12 06:25 PM

Hey I should have mentioned, being able to eat and drink correctly while rolling is another big deal. If you can do this you will shave off a tonne of time spent at 0 km/h wolfing down massive amounts of food and drink, then sitting or lying around feeling like crap. Much better to ride a little slower and a lot smarter. take er easy, sip and nibble as you go, and let the kms tick by. If i had a nickel for every new distance rider ive seen lying at the side of the road after going too hard, bonking and then eating an entire subway (and ive definitely been there myself), why i'd have a small pile of nickels.

jeffpoulin 09-15-12 12:33 PM

I live in the French alps, and it's hard to find any 100km ride around here with less than 2000m of climbing. Most people in our area have light racing bikes with wheels that cost way more than my bicycle, but I ride a touring bike with heavy-duty 36 spoke wheels and 700x35 tires. It's comfortable and not all that slow. I'm a pretty good climber and often pass "roadies" going uphill. Of course, they overtake me again on the downhills and flats, but the point is, you don't need light wheels to climb. It helps a little, but total weight (including the rider) and overall fitness is far more important when it comes to climbing.

stevage 09-16-12 12:01 AM

Cool - very good to know. Though I'm surprised the roadies are faster on the downhills - are they more aerodynamic?

Also, where in the French Alps? I lived in Grenoble for a year (2001-2), but wasn't much of a cyclist then. I tried to go for a hill climb with a friend once, but nearly died, only a few k's down the road...

You might also be able to help with an unrelated question: I'll be in Switzerland (Interlaken/Grindenwald area) around the 2nd week of October. Is it still possible to hire a bike and do a big climb or two, or do you think it will be too late in the season? Any suggestions?

jeffpoulin 09-22-12 12:37 AM

Quote:

Originally Posted by stevage (Post 14736165)
Cool - very good to know. Though I'm surprised the roadies are faster on the downhills - are they more aerodynamic?

Also, where in the French Alps? I lived in Grenoble for a year (2001-2), but wasn't much of a cyclist then. I tried to go for a hill climb with a friend once, but nearly died, only a few k's down the road...

You might also be able to help with an unrelated question: I'll be in Switzerland (Interlaken/Grindenwald area) around the 2nd week of October. Is it still possible to hire a bike and do a big climb or two, or do you think it will be too late in the season? Any suggestions?

Sorry, I just saw your post...

Not more aerodynamic, but heavier. I weigh 60kg which helps a lot on the climbs, but makes it hard to go very fast on the way down. Plus, I tend to be pretty cautious in the turns. Being more of a cyclotourist than a racer, I don't take as many risks.

I'm a bit north of Grenoble, near the Swiss border. Once you get used to the hills, they're really fun. It's seldom windy here, and I must say that I really prefer hills to wind. At least with hills, you know what to expect.

2nd week of October is iffy. Normally, the mountains below 3000m do not get snow that lasts for months until November. However, a cold, rainy day in the valley can be snowy in the mountains almost anytime. This year, we had snowstorms below 2000m once in August and twice so far this month. If it's sunny, you should be fine, but if it's cold and rainy, then watch out. If I had to give percentages, I would say there's an 80% chance that 2nd week of October will be fine, and 20% not. Sounds like a fun trip in any case, and if it snows, at least you'll have some nice scenery.

pmt 09-22-12 06:13 PM

Quote:

Originally Posted by mander (Post 14696060)
Hey I should have mentioned, being able to eat and drink correctly while rolling is another big deal. If you can do this you will shave off a tonne of time spent at 0 km/h wolfing down massive amounts of food and drink, then sitting or lying around feeling like crap. Much better to ride a little slower and a lot smarter. take er easy, sip and nibble as you go, and let the kms tick by. If i had a nickel for every new distance rider ive seen lying at the side of the road after going too hard, bonking and then eating an entire subway (and ive definitely been there myself), why i'd have a small pile of nickels.

Yes indeed. When we have a group that wants to really rock and roll a brevet, we make sure that all eating/drinking is on the bikes, natural breaks are taken as much as possible in remote areas, and everybody knows in advance what they need to do at each control. Our times are fast when we do that.

Of course, we also have fun on the "take your time" rides with sit-down lunch and stuff. Both ways are good.

hairytoes 10-08-12 09:06 AM

Quote:

Originally Posted by Chris_W (Post 14695026)
When climbing uphill at a constant speed, rotating weight is equally important as non-rotating weight. It is only when accelerating and decelerating that it makes a difference whether the weight is in a rotating part or not (and even then I think the difference is over-emphasized).

I'm not sure that is true at all. The difference is certainly not over-emphasized - try riding a bike with 900gm tyres, then try the same bike with 550gm tyres. You'll be amazed at how much harder the 900gm tyres are; but adding and removing 800gm from a saddlebag will be insignificant.

Riding up hill *is* accelerating - you are doing work, which is converted to potential energy as you gain altitude. Force over time = impulse = change in momentum, therefore a change in the angular momentum of the wheels.

Steamer 10-08-12 09:17 AM

Quote:

Originally Posted by hairytoes (Post 14818233)
I'm not sure that is true at all. The difference is certainly not over-emphasized - try riding a bike with 900gm tyres, then try the same bike with 550gm tyres. You'll be amazed at how much harder the 900gm tyres are; but adding and removing 800gm from a saddlebag will be insignificant.

How do you know you aren't sensing the change in rolling resistance between the two tires rather than the change in mass? Generally, lighter tires with thinner casings and treads have lower rolling resistances.

zzzwillzzz 10-08-12 04:34 PM

to the op:
do you have any friends? borrow a set of nice road wheels with some 23s or 25s and take them for a short ride and see what the difference is like, quit all the guessing and handwringing and find out if how much of a difference it makes or doesn't make for yourself.

MetinUz 10-08-12 06:22 PM

Quote:

Originally Posted by hairytoes (Post 14818233)
Riding up hill *is* accelerating - you are doing work, which is converted to potential energy as you gain altitude. Force over time = impulse = change in momentum, therefore a change in the angular momentum of the wheels.

I am sorry, but this makes no sense.

Carbonfiberboy 10-08-12 09:03 PM

Quote:

Originally Posted by MetinUz (Post 14820401)
I am sorry, but this makes no sense.

Correct. However Mr. Toes has some grasp of the general theory.

Why do lighter wheels make you faster? If you could spin perfect circles and keep your forward and angular momentums perfectly even, a small amount of added weight would not affect your climbing particularly. However, most of us climb out of the saddle or even in the saddle by pushing on the pedals mostly during the downstroke. Why does this matter? After all, if one accelerates a heavier wheel or heavier bike, one gets the momentum back between power strokes, doesn't one? So why should lighter wheels, tires, and tubes make you faster? I've heard many inexperienced riders opine that heavier wheels should make you faster because then the bike wouldn't slow as much between power strokes. Why is that not true?

The answer to that rhetorical question is simple. Peak force is expensive. The reason we spin rather then mash is because we hope to reduce the maximum force of muscular contractions, thus sparing glycogen. Thus lighter wheels reduce the peak force provided by your leg muscles because you're accelerating less weight. Peak force being lower in those muscles, they last longer. Of course one could also maintain the force of the muscular contractions and go faster. Whatever. Of course I'm talking rim, tire, and tube weights, not hub weight. So one does have to look and see where the weight of the lighter wheels is being reduced.

One could also learn to pedal perfect circles and keep one's butt in the saddle, in which case wheel, tire, and tube weight would make no more difference than weight in the saddle bag, maybe less since the saddle bag is higher. I think I'm faster over a long day with light wheels which have bladed spokes and deep section rims. Though they are not as light as specialized climbing wheels, I think the aero more than makes up for it. I also like ~230 gm tires and light tubes.

islandboy 10-08-12 09:03 PM

Quote:

Originally Posted by MetinUz (Post 14820401)
I am sorry, but this makes no sense.

Gravitational force makes a steady uphill tempo an acceleration. If you are slowing down at a rate of 9.8 m/second(squared) in the vertical then you will not be 'accelerating'.

Homeyba 10-08-12 09:47 PM

Quote:

Originally Posted by islandboy (Post 14820991)
Gravitational force makes a steady uphill tempo an acceleration. If you are slowing down at a rate of 9.8 m/second(squared) in the vertical then you will not be 'accelerating'.

Sorry, there is no such thing as gravity (your physics teacher lied to you), the earth sucks!

hairytoes 10-09-12 02:23 AM

Quote:

Originally Posted by islandboy (Post 14820991)
Gravitational force makes a steady uphill tempo an acceleration. If you are slowing down at a rate of 9.8 m/second(squared) in the vertical then you will not be 'accelerating'.

As in you will not be gaining velocity.

You are doing work, exerting an upward force to overcome gravity. Force=mass*acceleration. This is high-school physics.

But lets forget the theory. To the people who doubt, try for yourself. Get tyres of similar construction, tread, same pressure but different weight. (just get same model tyre in different sizes). Ride. See how it feels.

Or you could just look at what the pros do. Flat TT = aero bike, often with quite heavy deep section wheels. Mountain stage? Lightest wheels they can fit.

howsteepisit 10-09-12 10:15 AM

You need to set your tire pressure by your weight on the wheel and the tire size. Setting the same pressure for tires of different sizes will give you an invalid conclusion. There are several calculators online on pressure required to get the preferred 15% deflection for different body weights and tire size. Here is a nice one:

http://www.dorkypantsr.us/bike-tire-...alculator.html

Homeyba 10-09-12 10:49 AM

Quote:

Originally Posted by howsteepisit (Post 14822608)
You need to set your tire pressure by your weight on the wheel and the tire size. Setting the same pressure for tires of different sizes will give you an invalid conclusion. There are several calculators online on pressure required to get the preferred 15% deflection for different body weights and tire size. Here is a nice one:

http://www.dorkypantsr.us/bike-tire-...alculator.html

That's kind of a silly calculator. It says I should be running 212Psi...or riding on massive balloon tires. Don't think that's going to happen. I'll just go by what the tire manufacturer says


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