Stiffness vs. weight in climbing

what wheels are they?

jsull14 said:

I would like to hear what you think is more important for climbing. Overall stiffness of the bike or overall weight of the bike.

Personally, I want a stiff bike that responds to the power I'm putting to the pedal. If the power goes other places than to forward (or upward) momentum, you're losing speed.

jsull14 said:

I really want to improve my climbing.

Any thoughts?

Climb more. Something else to consider.

400 grams = 0.881849049 pounds

For a local hill climb we do, 7.5km - average 7% gradient with gradients of 12-15% for most with a couple descents. 4 lbs = approximately 30 seconds of time. 20 more watts of power = 1 minute.

I'll take stiff wheels and lose a pound then go train harder. But that's just the way I see it. YMMV.

jsull14 said:

I would like to hear what you think is more important for climbing. Overall stiffness of the bike or overall weight of the bike.

I just bought a set of wheels that is 400g lighter than my previous set. I thought I would fly up my local steep hill with these wheels but the reality, so far, is that I have been 2 minutes slower than I was before (37.5 minutes with old wheels, 39.5 with lighter wheels after two attempts). I am a little bummed and still searching.

I am not a super experienced cyclist but I can definitely feel that the wheels are a little flexy. In other words, not very stiff. I imagine this is expected because there is less material in the rim. The wheels do, however, roll great on flats as the hubs are like glass but I really want to improve my climbing.

Any thoughts?

You can get light wheels and yet stiff. I think you made the wrong wheel choice... you could have posted here for recommendations before you made the leap.

dm69 said:

what wheels are they?

The wheels are Neuvation R28 SL2. I did a lot of research and these wheels have gotten very good reviews. Maybe they are stiffer than I give them credit for. Or maybe I am looking for an excuse for my poor cycling results. But they just feel soft.

jsull14 said:

The wheels are Neuvation R28 SL2. I did a lot of research and these wheels have gotten very good reviews. Maybe they are stiffer than I give them credit for. Or maybe I am looking for an excuse for my poor cycling results. But they just feel soft.

BobbyOCR is about to post a full report on the R28 and we'll have another point of view. And for what's it worth, might be worthwhile letting us know what was your "previous set".

jsull14 said:

The wheels are Neuvation R28 SL2. I did a lot of research and these wheels have gotten very good reviews. Maybe they are stiffer than I give them credit for. Or maybe I am looking for an excuse for my poor cycling results. But they just feel soft.

I've had a set of the R28 Aeros for about 6 weeks now (maybe a bit longer). I think they get great reviews because for the most part the people upgrading to them are coming from very low end wheels.

Are these wheels worth their low price tag? I think so. At 1500 grams or so do they compare with say Neutrons or Kysurim SSL/ES? which give or take a few grams are about the same? Not even close. From a stiffness point of view .. well they aren't.

For a climbing bike I'd take a stiff overall setup as opposed to shaving a few grams.

--brett

sogood said:

BobbyOCR is about to post a full report on the R28 and we'll have another point of view. And for what's it worth, might be worthwhile letting us know what was your "previous set".

Alex 298r was my previous set which came stock with my 2006 Specialized Roubaix.

Well, with only two attempts done, there could be other issues, like maybe your body is not performing optimally for some reason.

It'd be hard to believe that wheels were so flexy that they'd add an additional 2 minutes to a 35 minute climb. I think you ought to look elsewhere for the time loss.

As for stiffness vs. lightweight. I'd go for the stiffer set, first. Not only does a stiff set climb more efficiently, but it also--and this is the best part--descends better. Mind you, this is lateral stiffness we're talking about. Between all wheels, vertical stiffness is virtually a wash, and any differences in vertical stiffness are lost in tire deflection.

How do you know that your Neuvations are laterally less than stiff? Do you get brake rub while climbing?

Did you change tires? Pressures? Anything else on the bike?

I don't know how Neuvation R28 SL's rate in lateral stiffness. They're definitely not lightweight, but wheel weight (or more specifically, a wheel's moment of inertia) matters very little on a climb....at least until the grade gets really steep.

I'm with alienator here. There are so many considerations that could account for most or all of the time difference that I don't know why you think it's the wheels. If you had a power meter and if you rode the climb at the same (or higher) constant power after the wheel change and if you were riding the same tires at the same pressure and if your body weight was the same and if the wind was essentially the same, then you could say with some confidence that the wheels are the issue (because that's about all that's left). But, if you don't have a power meter, then there's absolutely no way to know what caused the time difference.

jsull14 said:

I would like to hear what you think is more important for climbing. Overall stiffness of the bike or overall weight of the bike.

I just bought a set of wheels that is 400g lighter than my previous set. I thought I would fly up my local steep hill with these wheels but the reality, so far, is that I have been 2 minutes slower than I was before (37.5 minutes with old wheels, 39.5 with lighter wheels after two attempts). I am a little bummed and still searching.

I am not a super experienced cyclist but I can definitely feel that the wheels are a little flexy. In other words, not very stiff. I imagine this is expected because there is less material in the rim. The wheels do, however, roll great on flats as the hubs are like glass but I really want to improve my climbing.

Any thoughts?

Since the grams of rims affect climbing more than the ones from frame or stem due to the 'rotating weight' and assuming that 200g is gained from rims while another 200g is from hubs/spokes, you can consider the weight saving is actually 200*2+200=600g.

According to what I read somewhere, 1 more KG will make you lose 3 seconds in a 1-KM climb with medium grade.

37.5 minutes climb may roughly be translated to a 10 KM medium climb.

Thus, 10 * 3 * 0.6 = 18 seconds. That's what you should expect to gain by switching to 400g lighter wheelsets with the same stiffness.

In fact, After I tested the two sets of my wheelsets on a local hill(4.3km, 6-7%) for many times, I got almost the same best time for both. The lighter one weights less than 1500g and I can feel the flexibility while descending. Another one is Shimano 7701 weighting 1700g.

Few points here: that 2 minute time loss wasn't due to the wheels.

The neuvation aren't exactly cutting edge wheels...They are light for the price YES but they dont live up to there name of being aero and they are probably quite flexy aswell. Quality of bearings is an issue aswell.

IMO if you are going to buy fast wheels then go the whole way and jump ABOVE the Ksyriums and into the league of Rolf Vigor's American Classic Mag's FSA rd488 etc.

Bearings, Aero and stiffness are the main concerns when buying wheels thats why I bought the FSA rd488.

PS: I dont expect the FSA's to help reduce my climbing times anything crazy on different days and moods my TT up a 7km rolling Hill can go anwhere between 14 and 17 minutes the wheels are claimed to maybe buy 30secs to a minute over an hour on a flat TT. So in other words the FSA have been tested to reduce my time on this hill by about 7-15 seconds I guess that a set of Neuvations would buy you little at all due to the flex and unaero box rim.

To me a few seconds are worth it but its all about the mind and legs! and a new set of wheels could be the difference of a bad mood and a good mood on any given day which could buy me minutes instead of seconds.

Buying a set of wheels can be justified much more than buying a set of handlebars which are 30 grams lighter anyway. 30 grams wont buy you a centimetre of speed :p

I might have missed a reply on this but do you have the same tires and tubes? Tires make a tremendous difference in how a bike rides, rolls, feels, everything. Tires and tubes can vary wildly in weight so you might have inadvertently put back a bunch of that 400 gram weight loss.

On the weight loss bit - was the 400 grams an actual weight difference (on a scale) or is it a comparison between manufacturers' weights? Manufacturers' weights are notoriously inaccurate so actually weighing the wheels (or the bike with the different wheels) might be a good idea. Regardless, a pound of weight is significant when you pick up the bike, but from a riding point of view (with the exception of my questions below), the weight difference is minor. For example, losing 400 grams on my bike would drop 0.5% of my total rider+bike weight. I would bet that if it was in rims/tires I could feel the difference in a very hard acceleration from a low speed, but on a long, many-minute climb? No way. I climb the same with a +/- 1 lbs difference. It's when it's +/- 10 lbs that it makes a difference.

On that note, is your style to stand and rock the bike back and forth? Or are you a sit and spin type of rider? The former tends to re-accelerate the bike a lot and rotational inertia will be a little more important - when I am in difficulty my bike slows noticeably between downstrokes. The rocking will exacerbate any flexiness in the wheels - my rim will sometimes rub my brakes. The sit'n-spin types tend to climb at a frustratingly steady pace and is much less sensitive to inertial differences between wheels. Generally speaking I am the former type of climber so I notice those things.

cdr

sideshow_bob said:

I've had a set of the R28 Aeros for about 6 weeks now (maybe a bit longer). I think they get great reviews because for the most part the people upgrading to them are coming from very low end wheels.

Are these wheels worth their low price tag? I think so. At 1500 grams or so do they compare with say Neutrons or Kysurim SSL/ES? which give or take a few grams are about the same? Not even close. From a stiffness point of view .. well they aren't.

For a climbing bike I'd take a stiff overall setup as opposed to shaving a few grams.

--brett

I think they'd compare better than ksyriums in aerodynamics and probably stiffness. The R28 aeros aren't up to the standard of wheels like Neutrons, but they feel better than their price. A couple of thousand km will tell if they are any good. They aren't laterally stiff due to poor hub design (narrowly spaced, though high, flanges), poor spoking pattern (1 cross) and low spoke count. It also depends on rider but they are stiffer than R550s.

I would take a stiff wheel, but more training will make you go faster, equipment will never do that.

carpediemracing said:

On that note, is your style to stand and rock the bike back and forth? Or are you a sit and spin type of rider? The former tends to re-accelerate the bike a lot and rotational inertia will be a little more important - when I am in difficulty my bike slows noticeably between downstrokes. The rocking will exacerbate any flexiness in the wheels - my rim will sometimes rub my brakes. The sit'n-spin types tend to climb at a frustratingly steady pace and is much less sensitive to inertial differences between wheels.

So what about the style of stand but don't rock the bike side to side? Wouldn't that minimise the lateral flex of the wheels and also be more energy efficient?

Maybe because you thought you had an advantage of lighter wheels you went out harder on the bottom and lost more time on top?? I doubt youve got split times up the hill, but if you did, youd know if you went out harder on the bottom and lost time at the top.

What we do to ourselves mentally has a bigger impact than our equipment most of the time.

Ray

sogood said:

So what about the style of stand but don't rock the bike side to side? Wouldn't that minimise the lateral flex of the wheels and also be more energy efficient?

NO. Sitting is more efficient because you only use a few muscles however its not all about efficiency so many people sacrifice efficiency for more leverage and power because they can use there back and arms whilst standing and rocking the bike. Standing and not rocking is less efficient and isn't any more powerful...puts a lot of strain on your abs aswell even though they aren't contributing to the pedal stroke.

I am a stander on short hills and I am a sit and grinder on long hills

carpediemracing said:

I might have missed a reply on this but do you have the same tires and tubes? Tires make a tremendous difference in how a bike rides, rolls, feels, everything. Tires and tubes can vary wildly in weight so you might have inadvertently put back a bunch of that 400 gram weight loss.

On the weight loss bit - was the 400 grams an actual weight difference (on a scale) or is it a comparison between manufacturers' weights? Manufacturers' weights are notoriously inaccurate so actually weighing the wheels (or the bike with the different wheels) might be a good idea. Regardless, a pound of weight is significant when you pick up the bike, but from a riding point of view (with the exception of my questions below), the weight difference is minor. For example, losing 400 grams on my bike would drop 0.5% of my total rider+bike weight. I would bet that if it was in rims/tires I could feel the difference in a very hard acceleration from a low speed, but on a long, many-minute climb? No way. I climb the same with a +/- 1 lbs difference. It's when it's +/- 10 lbs that it makes a difference.

On that note, is your style to stand and rock the bike back and forth? Or are you a sit and spin type of rider? The former tends to re-accelerate the bike a lot and rotational inertia will be a little more important - when I am in difficulty my bike slows noticeably between downstrokes. The rocking will exacerbate any flexiness in the wheels - my rim will sometimes rub my brakes. The sit'n-spin types tend to climb at a frustratingly steady pace and is much less sensitive to inertial differences between wheels. Generally speaking I am the former type of climber so I notice those things.

cdr

I was using weight weenie info and manufacturer info to get the weight comparison.

I generally like to sit and spin, but the hill I was riding is very steep so it requires a lot of standing. It's about 10% for 3.8 miles. (It's Sierra Rd. which is actually part of the Tour of California. Check out that wall amgentourofcalifornia.comstage3.htmlOpen ↗)

I was riding Conti GP4000s on my other rims but they won't fit these rims so I'm riding Hutchinson's.

I realize now that I need to do a more scientific test with the same wind/weather conditions, same tires, and same heart rate average before I can draw any conclusions.

dm69 said:

NO. Sitting is more efficient because you only use a few muscles however its not all about efficiency so many people sacrifice efficiency for more leverage and power because they can use there back and arms whilst standing and rocking the bike. Standing and not rocking is less efficient and isn't any more powerful...puts a lot of strain on your abs aswell even though they aren't contributing to the pedal stroke.

Sorry I didn't make it clear earlier but I was comparing standing without rocking vs with rocking, as a way to mimize the effect of wheel flex on energy transmission loss. I appreciate that sitting is the most energy efficient, but the question here is whether standing without rocking on a 'laterally flexy wheel' is more effective given the hardware limitation?

sogood said:

the question here is whether standing without rocking on a 'laterally flexy wheel' is more effective given the hardware limitation?

I think it would be more effective to open the brakes up a bit. Standing without rocking is relatively inefficient - it's usually done when a rider is just about to blow up. The most famous example I can think of is Fignon responding to Lemond's multiple attacks on the last climb of the 89 Worlds. Poor Fignon looks like a beginner racer as he desperately tries to stay on Lemond's wheel. A Fignon in control would heavily rock his bike. Standing with rocking would be better, and the majority of the "inefficiency" is from the rim rubbing the brake. Eliminate that and you'll be fine.

If the rim does rub the brake, it's actually a stiff rim but flexy (or low tension) spokes. A flexy rim flexes mostly below the hub. Spinergy Rev-X's suffered from having too stiff a rim and too flexy spokes. The rim would rub and everyone would complain "it's too flexy" when in fact it was the spokes that were allowing the rim to tilt relative to the hub. On the other hand, if you look at old front-on shots of pros (say from the 80's), usually you can see significant rim flex and bottom bracket sway. The rim flex is inevitably below the hub level, indicating a light/flexy rim.

cdr