horinorbi1993

Hi,

I am planning to buy a Look 795 Blade RS bike, though I am not sure about which size should I go for. My dimensions: 181cm (5′ 11.26″) height, 83cm (2′ 8.68″ or 32.68") inseam, 78kg (172 lbs) weight. I am not that flexible, don't do races, only longer rides.

I currently ride a Cervelo R2 (2017) in size 56cm (original 100cm stem) and I am happy with it. This let's me assume that from the Look 795 - despite the 10cm difference in the stem length as well differences in top tube length, etc. - the size L would be the right one for me (unfortunately there is no Look dealer in my country, so I cannot try it in advance). What do you think?

Cervelo R2 geometry: cyclesmith.ca/product/cervelo-r2-105-211656-1.htm
Look 795 Blade RS geometry: lookcycle.com/at-en/products/bikes/road-bikes/aero/795-blade-rs-disc-chameleon-mat-glossy

Thanks in advance!
Norbert

Dean V

From the chart it would seem that the Large is nearest to your Cervelo but with a bit more reach.
But I would say that before spending a large amount of money on a bike like that I would go to a reputable bike fitter with your existing bike.
Get a fit done and then discuss with them if the Look would work for you.

DaveSSS 

Interesting body dimensions. 5 inches taller with the same 83cm cycling inseam I have. That should make your saddle height around 73cm. I'd buy a small and use no spacers with a -17 stem to get the bars low enough. Buying a large would give you the fit of a touring bike on a $4K frame. I'd split the difference and buy a medium. If you really need that much stack, maybe an endurance frame is really what you need.

horinorbi1993

Thanks for your comments. Quite true, a bike fitting is definitely necessary, already booked it.

Though I am really surprised that this brand has such a limited distribution channel - I live in Austria and it is basically impossible to get one (at least to try one before buying).

horinorbi1993

Hi,

I had the bike fitting and the following dimensions resulted:

Bike frame & crankset:

• Effective seat tube angle: 75 deg.
• Frame reach: 385 mm (with 130mm stem, so altogether 515 mm)
• Frame stack: 580 mm
• Crank length: 172,5 mm.

Also, my saddle height was 776 mm.

As I compare the 795 Blade RS frame geometry table with my fitting dimensions, it seems that the Large size would almost perfectly fit me, since it has 578 mm stack and 396 mm reach (including the original 110 mm stem that would result in 506 mm). What do you think?

Many thanks for your help,
Norbert

DaveSSS 

You were way off on cycling inseam if your saddle height is over 77cm. The 75 degree STA makes no sense, since even the smallest frames are rarely that steep. STA must have a seatpost setback to go with it or it's meaningless. The handlebar reach must also be considered and added to stem reach. Some bikes come with 80mm reach bars and others may have 100mm.
I just looked up the 795 geometry and they show a 75.8 degree STA for all sizes. This is a TT or triathlon bike, not an all around. Consider a 785.

Dean V

I think you should discuss it with the person that did the bike fit.
They are in the best position to give an informed opinion.

horinorbi1993

Thanks for your insights! Will definitely consult the bike fitter before I buy a bike.

Moisture

And what about top tube length? That matters too.

385mm reach with a 130mm stem, plus drop bars (unless we are talking effective top tube length of 580mm or less) sounds like the sort of dimensions that would work well for me. I am 189cm tall, 190lb and 87.4cm cycling inseam. Are you sure you wouldn't feel too stretched out or uncomfortable on longer trips like this?


agree that 75° STA is absurdly steep and just unnecessary. 580mm stack sounds fine, but for you, I think I'd go shorter on the stem and try to get a bit lower stack wise, unless you want the handlebars to be a bit more level with your saddle - necessary for such a long reach your LBS chose.

horinorbi1993

Thanks for your input, highly appreciated. Well, I was somewhat also surprised with the results of the bike fitting. I guess he tried to put me in a littlebit more stretched ("aerodynamical") position, as I told him that I am looking into the aero bikes direction. The fitting position was not uncomfortable though, I felt only that my forearm muscle must get used to it.

After the bike fitting I have changed the original 100mm stem on my Cervelo R2 to a 120mm one, and it feels much better (on the original stem I had to shrink my body), so the fitting results seem to be realistic. Now my reach on the Cervelo is 387mm + 120mm stem, so overall 507mm (just a bit shorter as in the bike fitting). The stack of the bike is exactly 580mm, so there is no deviation from the bike fitting result. The saddle height is also identical. This set-up on my cervelo with the new stem feels overall perfect.

As you say, however, a bike like the Look 795 Blade RS would be more aggressive. That's why I would definitely like to try a new bike before I buy it, even if bike shops often don't offer this possibility... Although I am not a super pro rider (do around 4.000 km in a year), I live in a relatively flat area and almost never climb (only on indoor trainer), which - besides the awesome appearance - somewhat justifies an aero bike. I know, there are only marginal differences to an endurance bike, aero trend is BS, etc...

Anyways, thanks again.

Moisture

Very happy to hear that you found something which works well for you.

A couple points -

Saddle setback. Have you tried to experiment with this in conjunction with saddle height?

Crank arm length? Standard 175mm would likely work fine (if thats what your bikes use.) You can maybe try going a bit shorter to experiment.

Habdlebar drop. Do you want something more stretched out with a less aggressive drop? Or more drop, less reach?

does 580mm for stack sound good to for you? I'd say maybe slightly less stack, slightly shorter stem,.but obviously hard to say without seeing you or your bike fit.

luckily, you are a well proportioned individuals, so you have options here.

Moisture

One more key point. If 120mm stem change felt good for you I doubt it would be an issue. Seems to me you are in good shape. But that sort of reach figure sounds like it may compromise your lower back for real world long distance riding. Keep that in mind.

The road bikes I've been looking at in XL size have a mostly 590mm top tube , roughly 390-400mm reach and maybe 110mm stem. This is what should work well for a fit person around 6ft 2 or so. If you can maintain this position, you got one hell of a core and lower back...

horinorbi1993

Well, I wouldn't say I can maintain it for a very long time, I usually need a stretching break (by getting on the top of the handlebar) around every 15-20 minutes. And, what I forgot to say, currently my saddle is in the most forward position possible, which may also indicate that the overall reach of 507mm (387 reach + 120 stem) is a littlebit on the long side. But I definitely wouldn't go back to the old stem, so the truth probably lies somewhere in the middle. Regarding strong core: based on the advise of the bike fitter I usually do planks at home to have a stronger abdominal muscle and be able to remain in the aero position, I guess it also helps.


Really thanks for the comparison, quite insightful. Can I ask what kind of bike you are riding - endurance or aero?

Branko D

There's no real problem with long and low for long distance riding once you've become accustomed to it. Core work (involving weights) and a healthy weight definitely helps.
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Rode this for many 200km and some 300km rides, without pain or discomfort afterwards.

It’s not the kind of fit I started road cycling on, though. Fit can be a movable target. ​​​​​​Also, there are limits where you start to get issues if you go over them - best discovered by experimentation.

If you are 181cm tall I don't think the L could possibly be too low for a reasonably fit rider; at 178-179cm tall I would consider an M with no spacers and a 110mm -17 stem, which would be a bit higher than what I ride and more of a "comfort" fit.
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Moisture

I agree with one of the posters suggestion to look into a size medium, I think this would make it worth it for you to change bikes as you can get lower due to a smaller stack.

Having your seat mounted all the way forward more than likely is an issue in terms of the way you are being balanced over your bottom bracket.

You said that you've already tried to move the seat back a bit while using an adequately shorter stem, correct?

Me personally, I've spent very little time riding a road bike that fits. From the perspective of road biking, im more endurance oriented with a taller stack to save my back. My legs are a bit longer than average torso / inseam measurements. My carbon felt mountain bike is set up aggressively with 465mm reach, 640mm stack, and a 110mm stem mounted +10° which results in a roughly 5cm bar drop. Stock stem length was 90.

If the stem didn't have such a steep rise in degrees, I'd split the difference and go 100mm. This is the most i can offer you from my perspective of real world fitting in a performance oriented perspective.

For a road bike, I think I'd be looking at a reach of around 395, pretty high stack at 650-660, and 80-100mm stem. I can go super long on overall reach if the stack is high enough and I don't care too much about real long distance riding requirements.

horinorbi1993

Well it seems that everybody suggests size M, this means something Nice bike btw!

Thanks for the help!

Moisture

Id say you are somewhere between both sizes and should try both.

Dean V

Leg length also plays a big part. I am 1.80m with a 785mm saddle height. If I set up my medium Giant TCR I would have a saddle to bar drop of around 15cm+ which is too much for me and would be for most people.

Branko D

That's true, leg length is a factor when it comes to saddle height, and that's going to obviously impact how tall is the front end. Also, there's going to be a range of acceptable saddle heights for a given person (especially if cleat fore-aft changes), some people prefer it as high as they can manage, and that obviously dictates the bars need to be significantly higher up, some don't, so the bars go lower.

I'm a slight bit shorter, yet my saddle height is 727mm (measured from center of BB through the center of the seatpost clamp to the top of the saddle). I could ride with maybe 10mm taller saddle but it wouldn't be as comfortable to do for long distances. 83,5cm inseam, so not quite long legs ;P

Interestingly, my saddle height (which I got to mostly through experimentation, basically) falls just about 5mm short of what you get using the Lemond method (corrected for about 5mm lower stack height of modern pedals and shoes).