Bike Fit Question

[Duane_Bosch]

Ok so this is a bike fit question but I'm not going for a bikefit.

 

I don't believe in Bikefits for enduro style bikes. The position isn't static enough for it to make sense IMO. However, I'd like to match my saddle height of my Reign to that on my roadie.

 

The conventional wisdom is to match bb to saddle rail measurement. But I think it's more complicated than that. Pedal thickness, crank length etc all play a role. Plus I'm a midget so every mm makes a difference. Shouldn't I rather match the saddle rail to the top surface of the pedal at full extension?

[Psyrax]

I think you have answered your own question. Your enduro and road bike is worlds apart from each other. Go with a saddle height thats comfortable.

[SwissVan]

Ok so this is a bike fit question but I'm not going for a bikefit.

 

I don't believe in Bikefits for enduro style bikes. The position isn't static enough for it to make sense IMO. However, I'd like to match my saddle height of my Reign to that on my roadie.

 

The conventional wisdom is to match bb to saddle rail measurement. But I think it's more complicated than that. Pedal thickness, crank length etc all play a role. Plus I'm a midget so every mm makes a difference. Shouldn't I rather match the saddle rail to the top surface of the pedal at full extension?

I put the pedal at BDC or 6 o’clock and measure to the top of the saddle along the center line of the seat tube for all my bikes (XC, tri and road) using the same measurement . This is a starting point and then I fiddle a bit until comfortable. Usualy the mtb and tri bike end up a few mm lower.

 

How does sag affect your seat height measurement on an enduro bike?

[DieselnDust]

Ok so this is a bike fit question but I'm not going for a bikefit.

 

I don't believe in Bikefits for enduro style bikes. The position isn't static enough for it to make sense IMO. However, I'd like to match my saddle height of my Reign to that on my roadie.

 

The conventional wisdom is to match bb to saddle rail measurement. But I think it's more complicated than that. Pedal thickness, crank length etc all play a role. Plus I'm a midget so every mm makes a difference. Shouldn't I rather match the saddle rail to the top surface of the pedal at full extension?

 

Pedal top to saddle top. Adjust the saddle to ensure the wide part is a similar distance behind your B.B for both bikes.

The rest will take care of itself from there. You may find that the brake hoods will be a little far away at first so be prepared for a shorter stem initially

[Duane_Bosch]

How does sag affect your seat height measurement on an enduro bike?

Thanks for the info.

 

Sag doesn't affect it. The seat height to BB is static. 

[stefmeister]

I put the pedal at BDC or 6 o’clock and measure to the top of the saddle along the center line of the seat tube for all my bikes (XC, tri and road) using the same measurement . This is a starting point and then I fiddle a bit until comfortable. Usualy the mtb and tri bike end up a few mm lower.

 

How does sag affect your seat height measurement on an enduro bike?

It depends if you set up seat height with sag. More sag on your  rear end will change geometry - shorten reach, reduce stack height and decrease STA. But then again you're also running sag upfront which balances that out, so the effect would be minimal.

[Duane_Bosch]

It depends if you set up seat height with sag. More sag on your  rear end will change geometry - shorten reach, reduce stack height and decrease STA. But then again you're also running sag upfront which balances that out, so the effect would be minimal.

Huh? The saddle to bb is static. 

[Captain Fastbastard Mayhem]

Huh? The saddle height to bb is static.

yeah, but distance behind BB changes as your sag increases. That's what he was referring to. 

[stefmeister]

Huh? The saddle height to bb is static.

Yeah true, but fore and aft of the saddle position will be affected.

[DieselnDust]

the measurements are taken static so sag doesn't come into it.

[DieselnDust]

Yeah true, but fore and aft of the saddle position will be affected.

 

 

Yes it will but this is transient. The suspension Is cycling through its travel all the time but the bb is attached the downtube to the headtube to the fork to the bars and those measurements are all static.

ignore the wheels and where they are in space. He just wants to get the biomechanical interfaces similar and as long as the bike isn;t a floating bb design, it won't matter what the suspension is doing.

There are some bikes with silly actual seat tube angle where this is an issue, but on most bikes with sufficient anti squat this isn't an issue.

[Duane_Bosch]

Yeah BB isn't a floating design. It's a Giant Maestro link.

 

All I'm trying to do is get my leg extension on my MTB to match the same on my roadie. Hence the question about top of pedal to top of saddle which makes the most sense to me.

 

I can't control the suspension variable and frankly I don't think it's a factor because the bb to saddle is fixed. But I concede that I might be wrong here as per Stef.

 

Besides. The shock locks out when I'm climbing.

[DieselnDust]

Your thinking is good. I think there's also way too much emphasis on bike fit. Its always good to get one done at a point to ensure you haven't drifted too far from common sense but baajeeeezzarz can people take it to the next level. Any decent bike fitter will give you a range anyway as your flexibility changes day to day hour to hour.

I have 6 different pairs of biking shoes all with different stack height and I haven't fallen apart yet. As long as the pedal top to saddle top is within 0.5cm to1cm of each other between the two bikes you probably won't create long term injuries.

You just don't want the distance between the two parts to be growing causing you to stretch more. That would be bad

[Karman de Lange]

Put your heel on paddle, paddle backwords and adjust saddle till you don't rock from side to side and for good luck go 5mm lower.

 

always err on the low side, 10mm to high can cause @#%#$ of issues, 10mm to low you won't even notice it

 

Re your orginal question ..  Top of saddle compressed to top of paddle.

 

We shrink about 10mm as day goes on , so if you worried about mm's , probably best to do bikefit in the evening when you the shortest.

[Grebel]

Why not sit on the roadie and measure the angle of the bend in your knee with your heel on the pedal and transfer the same bend to the MTB with your heel in the same place?

[dasilvarsa]

If the cranks are the same length on both bikes and the pedals are the same then center of bb to top of saddle should work. Some saddles compress more than others and not all pedals are the same thickness.

 

Having said that. MTB setup and road bike setup are a little different .

 

I had a bike fit done a couple of years back and for my inseam of 75 cm the best position for the saddle is 65 cm from the center off bb to the top of a hard saddle. Also a 5 mm nose up on the saddle gave me the most comfortable ride with a 1 cm setback.

I've copied this setup to 3 MTB and it works just fine.