How much difference does a kilo make?

crimpshrine

I am considering a change from a Trek with Ultegra SL to an RS2 with SRAM force. I undertand it is kind of a sideways step rather than a full on upgrade but the Trek is not the right size for me and my friend has offered a decent price for it so the RS2 will not cost me much at all.

Weight difference will be nearly a whole Kilo as I will be changing wheels too. How much does a Kilo difference on a bike make? I did not think it would make much difference when you factor in 58kilos of me but the I started thinking of it as a percentage of the Treh and it sounds a much bigger difference!

Will I notice a bit difference or will it be just a little?

Also how does the Force compare to Ultegra SL? I know the shifting is different.

Thanks.

Martin Van Nostrand

On climbing, the number of 1% per pound has been used, so 2.2%.

Elganesh

Regarding weight, you may notice a difference in performance but some say that's it's better to lose a weight from yourself than your bike. Most of the energy you use when riding will actually be used to defeat the force of air resistance (approx 90%) so bike weight isn't as big a factor as people think. The best way to improve climbing etc is to get out there and train.

With respect to your groupset, I have a Trek with Ultegra (being about 100g heavier than SL and a different finish) and have been told it's equivalent to SRAM Rival so I would say Force would be better than Ultegra.

robbarker

Add your weight, a couple of bottles, clothing and your tool pouch to the weight of the bike and than work out the percentage difference. 1% ish? It won't matter a jot unless you'reracing at a fairly high level.

You're invariably better off spending the money intended for marginal upgrades (assuming the existing stuff isn't knackered) on some decent tools and materials to keep what you do have running sweetly, or on a nice training trip away.

whyamihere

It doesn't feel like a huge difference uphill, but a kilo will have a big effect on handling, depending on where it is due to weight distribution. Wheels are a very good place to lose weight because it's all rotating mass. The lighter your wheels are (especially at the rim) the faster the acceleration. Same applies to cranks etc.

Overall, a lighter bike will be a lot more responsive to being thrown around. Depending on your riding style, this may or may not be a good thing. If you're into relatively sedate rides, weight's not that important. If you like throwing the bike into corners fast and need it to respond quickly, lighter is better.

Smokin Joe

Elganesh wrote:

Regarding weight, you may notice a difference in performance but some say that's it's better to lose a weight from yourself than your bike.

Not that losing weight from your bike prevents you from also losing some yourself...

weapons

The guy is 58kg - not sure there is much more weight to lose!

GavH

I recently upgraded my '05 Carrera Virtuoso. Removed the saddle and seatpost and swapped for a CF post and Spesh BG Toupe saddle saving nearly half a kilo. I also swapped out the all metal front forks for a CF pair with alloy steerer, shaving (actually more like hacking) another 0.6 kgs off. So all in, I reduced the weight of the bike by more than a kilo. I can honestly say that my first trip out the bike did feel more sprightly and responsive, but I wasn't sure if that was weight or the fact that the CF components just give a totally different 'feel' which would skew my opinion?

As has already been pointed out, your saddle bag will add another half kilo as will each 500ml water bottle so I suppose it's all relative to what you're doing. If you wait a few days (or week or so) I'll let you know how much quicker my new Bianchi 928 C2C is over my alu bike when it arrives!

Hudster

As pointed out - the guy is 58kgs! I'm just a bit under that and notice small changes in weight to the bike, more so than heavier friends I think. A kg extra is not going to kill you and you'll be able to do all the same rides as before, but I'm sure you'll notice it, especially when you are so light yourself.

tenor

Go to www.smartcycles/bike_weight/htm
This refers to a study on the influence of weight on climbing performance.
The study concluded that a 250 watt rider of 200 pound bike/rider combination would take 19minute 21 seconds to climb a 5k @ 7% gradient.
Each additional pound weight would add 6 seconds to that time, thus for an additional kilo you could add about 14 seconds - about 1.2% to the ride time.
Alternatively an increase from 250 to 253 watts would compensate for the additional mass, which does not seem so difficult to acheive through training.
As you are lighter, you will probably be quicker than the base figure, of course.
14 seconds could be significant for a tour rider, but not particularly for any other form of cycling.
On the flat, weight makes little difference except to instant acceleration.
Only the combined weight should be considered.
Handling is much more likely to be linked to wheel and frame stiffness / geometry than a miniscule difference in bike weightt

crimpshrine

Thanks guys. I may stick to my bike then. I am sure I would notice the difference but for the sake of a few seconds I am not sure it is worth it. I do it for enoyment rather than racing. As I am pretty lightweight I also think the bike might become a bit too twitchy and skittish?

psiturbo

I have read that a kilo on the wheels is much more noticeable than on the bike itself because of centrifugal forces.

I do not think it is a big deal, you can almost lose a kilo by going to the bathroom after taking some Alli...

Smokin Joe

tenor wrote:

14 seconds could be significant for a tour rider, but not particularly for any other form of cycling.

Not just to Tour riders. Even the lowliest club racer would kill to save 14 seconds over 5k, and so would many sportive riders.

Frank the tank

The frame and wheels are the most important places to shave weight. I would think the place you'd notice the most difference is losing weight off the wheels. Groupsets are the least important place for weight saving.

John C.

On a hilly sportive, you have already done 100 miles in the last 7 hours and 3000m of climbing, you are now looking at iether Rosedale Chimney or Hardknott, now which bike would I rather ride for the next 15 minutes ? After that I'll be full on the brakes with my arms screaming at me to let go so I'm sorry but I'll have the lightest bike available even though I only weigh 9 and a bit stone.

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