BTLOS 30mm wheels for pure climbing?

[mcteague]

Originally Posted by fogrider

I stand by my comments based on my own results, your results. Your results may vary! I'm sure some of it is because of 'new wheel' affect but a PR is a PR. to be honest, I doubted too, this was with tubulars when I first got sucked into lightweight wheels...

But are you consistently 2-3 mph faster on the new wheels? I'm not questioning your experience but it does conflict with years of data on weight vs speed.

Tim

[thwart]

Originally Posted by mcteague

But are you consistently 2-3 mph faster on the new wheels? I'm not questioning your experience but it does conflict with years of data on weight vs speed.

Tim

Yep, that’s the key word.

A PR is certainly nice but day in, day out performance over time tells the tale… factors out the psychological aspect.

[Mark McM]

Originally Posted by fogrider

Tex, I've been to Texas...it's mostly flat, you certainly don't need climbing wheels! But lightweight wheels do make a bike feel quick! A 1250 gram wheel compared to aluminum wheels might be like 2mph on a climb. So, if on Alum wheels, you might be climbing at 10 mph, but on carbon, with the same power, you might be doing 12 or 13 mph.

So, if 1250 gram wheels makes you 2 mph faster on a climb, will 950 gram wheels make you 4 mph faster? I've used 950 gram wheels (FSE 20mm deep carbon tubulars) at the Mt. Washington Hill climb race, and if I'd gone 4 mph faster, I would have broken the all time time record for that climb. Yet I only averaged less than 0.1 mph faster. Should I go back to wheel maker and ask for my money back?

[bigbill]

Unrelated to average speed or weight, but if I got another set of wheels from BTLOS, I won't go with glossy again. My bikes are rarely clean other than the drivetrain. The glossy finish shows everything. I'll do matte next time. Otherwise, the Bitex hubs spin smooth and allow for direct pull spokes. I'm not sure if I'm faster but once we relocate to central Wyoming in the spring, I can do comparisons between the two wheel sets I have for my Open Min.d., OG Boyd Altamont or the BTLOS. The bike has a powermeter crankset so I can ride the same loop and compare power versus speed.

[fogrider]

Originally Posted by Mark McM

So, if 1250 gram wheels makes you 2 mph faster on a climb, will 950 gram wheels make you 4 mph faster? I've used 950 gram wheels (FSE 20mm deep carbon tubulars) at the Mt. Washington Hill climb race, and if I'd gone 4 mph faster, I would have broken the all time time record for that climb. Yet I only averaged less than 0.1 mph faster. Should I go back to wheel maker and ask for my money back?

With power to weight to speed, like many things in life, its diminishing returns. Back in the day, it was pretty tough to get wheelset under 1500 grams. And its really not the total weight of a wheelset that improves performance. Its rim and tire weight (and tube) or rotating mass that is furthest from the hub that really affects performance. Look at a modern wheel and how it's built to get to the final weight. With a 1250 gram wheel, the key is the lightweight rim and aluminum nipples. Lets say you're able to get to 950 grams. To get there, spec a carbon hub and spokes, then I would think the performance would be minimal. But if you can get to 950 with a lighter rim, you might be able to get more speed but there are other factors that will start to become a factor. But this is also why so many people like the TPU tubes, there's 60-80 grams savings for 30 bucks.

I'm not going say I know the physics behind it, but I'm speaking from experience. I've recently set PRs on segment and a 8.5 mile segment and a 0.2 mile segment, both uphill. In general, I know I climb faster with lightweight wheels and the bike just feels more responsive and fun to ride.

[fogrider]

Originally Posted by mcteague

But are you consistently 2-3 mph faster on the new wheels? I'm not questioning your experience but it does conflict with years of data on weight vs speed.

Tim

what data are you referring to? to specific, are we talking about weight or rotating weight?

[deluz]

Lighter weight wheels can feel faster but I think it is partly an illusion.
In my case rider plus bike weight is 160 lbs.
If I save 300g in wheelset weight that is 0.4% lighter.
At some point you are spending a lot more money and sacrificing robustness to lose a few hundred grams. Aluminum nipples on carbon rims are a recipe for corrosion.

[nmrt]

Lighter wheels are faster. For some riders, these savings mean a lot. But for many of us mere mortals, how much faster they are does not really matter in our hobby riding.

Even if I many not be significantly faster on my light 1100 g wheels, they sure do FEEL faster to me. And I would definitely pay for the FEELING of a faster speed.

I have only had carbon wheels built with aluminum wheels. My oldest set is about 6 years old. There has not been corrosion yet. Also, among my bikes, I have 8 carbon wheelset with aluminum nips. No corrosion yet.

I understand the science of why the corrosion can happen. But it has not happened yet.

Originally Posted by deluz

Lighter weight wheels can feel faster but I think it is partly an illusion.
In my case rider plus bike weight is 160 lbs.
If I save 300g in wheelset weight that is 0.4% lighter.
At some point you are spending a lot more money and sacrificing robustness to lose a few hundred grams. Aluminum nipples on carbon rims are a recipe for corrosion.

[Mark McM]

Originally Posted by fogrider

With power to weight to speed, like many things in life, its diminishing returns. Back in the day, it was pretty tough to get wheelset under 1500 grams. And its really not the total weight of a wheelset that improves performance. Its rim and tire weight (and tube) or rotating mass that is furthest from the hub that really affects performance. Look at a modern wheel and how it's built to get to the final weight. With a 1250 gram wheel, the key is the lightweight rim and aluminum nipples. Lets say you're able to get to 950 grams. To get there, spec a carbon hub and spokes, then I would think the performance would be minimal. But if you can get to 950 with a lighter rim, you might be able to get more speed but there are other factors that will start to become a factor. But this is also why so many people like the TPU tubes, there's 60-80 grams savings for 30 bucks.

I'm not going say I know the physics behind it, but I'm speaking from experience. I've recently set PRs on segment and a 8.5 mile segment and a 0.2 mile segment, both uphill. In general, I know I climb faster with lightweight wheels and the bike just feels more responsive and fun to ride.

When climbing, gravity affects all mass the same - it doesn't matter whether the mass is rotating or not. Only total mass matters when climbing, and not how the mass is distributed. If installing lighter wheels allows you to climb faster, it is because the lighter wheels reduced total mass. Reducing total mass can increase climbing speed at most by the relative proportion of the weight decrease. For example, if lighter wheels reduced the total mass of the bike + rider from 200 lb to 199 lb (0.5%), then at most the climbing speed will increase by 0.5%. But the actual increase in climbing speed will be less than this, because there are other drag forces on the bike (aero drag, rolling resistance, etc.), so the increase in speed with weight reduction will be in proportion to the the gravity force relative to the total drag force. So if gravity force is 50% of the total drag force, then reducing the weight by 0.5% will reduce total drag force by only 0.25%, so at best you'd go 0.25% faster.

As far as your recent PRs - there are many, many factors that effect performance, including the external factors of equipment, weather, road conditions, traffic, etc., and internal factors such as fitness, training, motivation, etc. Many of these factors can play a much larger role in performance than 200 grams of wheel weight.

[fogrider]

Originally Posted by Mark McM

When climbing, gravity affects all mass the same - it doesn't matter whether the mass is rotating or not. Only total mass matters when climbing, and not how the mass is distributed. If installing lighter wheels allows you to climb faster, it is because the lighter wheels reduced total mass. Reducing total mass can increase climbing speed at most by the relative proportion of the weight decrease. For example, if lighter wheels reduced the total mass of the bike + rider from 200 lb to 199 lb (0.5%), then at most the climbing speed will increase by 0.5%. But the actual increase in climbing speed will be less than this, because there are other drag forces on the bike (aero drag, rolling resistance, etc.), so the increase in speed with weight reduction will be in proportion to the the gravity force relative to the total drag force. So if gravity force is 50% of the total drag force, then reducing the weight by 0.5% will reduce total drag force by only 0.25%, so at best you'd go 0.25% faster.

As far as your recent PRs - there are many, many factors that effect performance, including the external factors of equipment, weather, road conditions, traffic, etc., and internal factors such as fitness, training, motivation, etc. Many of these factors can play a much larger role in performance than 200 grams of wheel weight.

I agree that the total mass is what matters. but the rotation of the wheel travels more because of ratio of Pi. it works like a pulley system or gearing. This does not just apply to climbing, like gearing, lower rotational mass means it's easier to rotate the wheels for acceleration and this applies to flat land acceleration also. Again, lighter wheels make any bike feel quicker and faster. And once you get use to it, you don't really think about it, but the data will show faster speeds.

[bikerboy337]

Not chiming in on the whole you’ll be faster or not discussion….

Just chiming in to say I’ve always had great luck with my BTLOS wheels.

I had a nice set built up last year.

DT240
GX 30/35 rims (30mm front 35mm rear)
Pillar spikes
Aluminum Nips
Came in at 1276g for disc brake wheels, no rim tape needed.

Have been perfect. We all know how nice DT240s are and the wheels are just fun. Have them on my 1x Open Mind with 30mm Corsa Controls, measure 31mm for me. No complaints. True, light, have lasted well so far and no issues..

My two main wheelsets are WTO45s and these and these clearly feel lighter when climbing and are more fun to climb and haven’t noticed any appreciable issues carrying speed on the flats over 20ish mph…. Feel like is a good mix of lightweight with some aero…

[gospastic]

Originally Posted by fogrider

I agree that the total mass is the majority of it. but the rotation of the wheel travels more becase of ratio of Pi. it works like a pulley system.

Do you ride with a power meter?

[Mark McM]

Originally Posted by fogrider

I agree that the total mass is the majority of it. but the rotation of the wheel travels more becase of ratio of Pi. it works like a pulley system.

I'm not sure what you are saying. The wheel travels the same distance as the rest of the bike. The bottom of the wheel is stationary, and the top of the wheel is travelling forward at twice the speed of the rest of the bike, so the average forward travel distance of the wheel is the same as the rest of the bike. Likewise, the front of the wheel is travelling down, and the back of the wheel is travelling down, which cancels out so the average vertical travel distance of the wheel is zero.

Let me ask you this: Say you are in an elevator moving upward to higher floors. Your identical twin is in another duplicate elevator, moving upward in parallel to your elevator. Both of you are holding identical bicycle wheels in your hands. Only, your wheel is spinning, and your twin's wheel is not spinning. Are you saying that your elevator takes more force or energy to travel to a higher floor than your twin's does, just because your wheel is spinning?

[sevencyclist]

I think the weight of the wheels are the weight of the wheels. Where energy is sapped is when rotating momentum is scrubbed by applying the brakes. It takes slightly more to accelerate back up to speed. So in a pure climb, whether weight is located in the rims or hubs or the frame does not change how much energy it takes to climb up. However, as soon as brake are used, then lighter wheels have slight advantage of getting up to speed quicker and lose less when brake applied.

[fogrider]

Originally Posted by Mark McM

I'm not sure what you are saying. The wheel travels the same distance as the rest of the bike. The bottom of the wheel is stationary, and the top of the wheel is travelling forward at twice the speed of the rest of the bike, so the average forward travel distance of the wheel is the same as the rest of the bike. Likewise, the front of the wheel is travelling down, and the back of the wheel is travelling down, which cancels out so the average vertical travel distance of the wheel is zero.

Let me ask you this: Say you are in an elevator moving upward to higher floors. Your identical twin is in another duplicate elevator, moving upward in parallel to your elevator. Both of you are holding identical bicycle wheels in your hands. Only, your wheel is spinning, and your twin's wheel is not spinning. Are you saying that your elevator takes more force or energy to travel to a higher floor than your twin's does, just because your wheel is spinning?

Sure, as a whole the wheel travels the same distant. Remember back in the day we had the cateye cyclecomputer? it used a magnetic sensor on the spoke that would register everytime it made a revolution. a conversion code had to be entered based on the wheel size. This converted the circumference of the wheel to the distance traveled by the wheel in the horizontal direction. the ratio is Pi, 3.14...

if you haven't tried lightweight wheels, you just don't know.