Seat height survey - supersport / road race

[Frame Maker]

As many of you may know I am building a custom frame and chassis for an RZ350 project. The question recently came up as to optimal seat height for a supersport / road race oriented bike. Here's the full thread...

https://bayarearidersforum.com/forums/showthread.php?t=546947

I'd like to get a wider audience with this specific question, so bringing this to the general forum with the above poll. The poll should be self explanatory... just looking for opinions on what you consider to be the optimal seat height for a supersport or road race motorcycle (please do not respond for other types of motos).

Here are a few assumption so that the comparison is apples to apples...

- I'm basing the height measurement taken at the middle (front to back) of the seat. I understand many sport bikes now have a bit of slant to the seat with front being lower than rear. So middle is the assumed measuring point.

- I am also assuming average height male riders of 5'8" to 6'0". If you have responded to the poll and are outside of this height range, please leave a comment in the thread so I can make a note.

- If you ride on both street and track, but have a different seat height preference for each type of riding, also leave a comment in the thread below.

I will leave the poll open for 1 week.

Thanks everyone. I appreciate the feedback:thumbup

Gratuitous project photo...

20210201_175724 by andbike, on Flickr

 

[buellistic]

I like my sport bike taller...2000 gsxr was close to a good fit. 2007 not.
My enduro lower 525 ktm..me 6.2"

 

[Shaggy]

6’4”/240lbs here.

I like the feeling of sitting on top of a bike, not inside it. I love the seating position on my R6 race bike, especially compared to my old K7 GSXR600 race bike. I look like a bear humping a tricycle on either bike....

www.cycle-ergos.com has the R6 at 33” and GSXR600 at 31.8”

I voted 33”+ because I wouldn’t mind an extra 0.1”.

 

[DannoXYZ]

I'm 5'6" and prefer race-bike seat around 31".

But even more important is handlebar height. I prefer handlebars around same height as seat. Feels better and easier to control.

Also top of tank should be lower than street bike so I can tuck in deeper behind windscreen. Doesn't need to hold as much gas anyway, just 1-1.5 gal needed.

 

[NoTraffic]

To add, seat height is also relative to other controls. A low seat with higher pegs may not be as desirable. From my understanding, most current sport bikes are at minimum 32" to enable increased lean angles and engine/component clearances of the pavement.

 

[DannoXYZ]

Ah yes, make bike as narrow as possible for more peg clearance. I use folding pegs, so they don't jack up rear-end when they start rubbing.

 

[stangmx13]

If we are talking "road race", I'd confirm that peg height is good. Then find a comfortable peg to seat distance so that your knees aren't too bent.

I need ~16" of peg height to not drag too much on an R6. Then I need ~17" of peg to seat distance for my knees. Add in the actual peg thickness and that's ~34" seat height to where I actually sit. I have long legs - 33" inseam - so I need that room. Im thinking about adding another layer of foam to my seat and raising the pegs another notch.

You bike is probably narrower at the pegs than a 600. So you may be able to get away with a slightly lower peg height. But it also depends a lot on your riding, your suspension, your tires, etc. You may find you need to experiment.

 

[Frame Maker]

First off, thanks to everyone who has taken the poll and especially to those who have left detailed feedback in the thread.

As many of the comments have suggested, any discussion about ergonomics should include peg location and handle bar location. Then adding peg width and lean angles to the picture the discussion becomes even more complex. That said, seat height is the most difficult to change once it has been designed into the chassis. Handlebars or clip-ons can easily be changed or adjusted for best hand location, and small brackets or aftermarket foot controls can be used to easily change peg location. Therefore I've isolated seat height as a single variable for this discussion as it is more difficult to change after the chassis has been designed and constructed.

Again, thanks to everyone for your input. Much appreciated:thumbup

 

[stangmx13]

First off, thanks to everyone who has taken the poll and especially to those who have left detailed feedback in the thread.

As many of the comments have suggested, any discussion about ergonomics should include peg location and handle bar location. Then adding peg width and lean angles to the picture the discussion becomes even more complex. That said, seat height is the most difficult to change once it has been designed into the chassis. Handlebars or clip-ons can easily be changed or adjusted for best hand location, and small brackets or aftermarket foot controls can be used to easily change peg location. Therefore I've isolated seat height as a single variable for this discussion as it is more difficult to change after the chassis has been designed and constructed.

Again, thanks to everyone for your input. Much appreciated:thumbup

Your bike will be unrideable if you put the seat at 30", then find you need the pegs at 17" to not scrape. So it may have been easy to move the pegs, but you'll end up moving the seat again anyways.

What's your peg to seat distance now? Do you find it comfortable? What's more important to you - comfort at stop lights or comfort while riding?

Also, its easy to make a seat taller and not that difficult to make it shorter. Just add or remove foam. Your seat looks stock so there should be plenty of foam to remove. Or add spacers. Or use a diff seat pan. Etc etc.

Aside from all that, be careful with measuring the seat height from the ground. Shock length, shock sag, and rear tire size can affect that measurement quite a bit. But it won't impact the distance from peg to seat.

 

[Frame Maker]

Your bike will be unrideable if you put the seat at 30", then find you need the pegs at 17" to not scrape. So it may have been easy to move the pegs, but you'll end up moving the seat again anyways.

What's your peg to seat distance now? Do you find it comfortable? What's more important to you - comfort at stop lights or comfort while riding?

Also, its easy to make a seat taller and not that difficult to make it shorter. Just add or remove foam. Your seat looks stock so there should be plenty of foam to remove. Or add spacers. Or use a diff seat pan. Etc etc.

Aside from all that, be careful with measuring the seat height from the ground. Shock length, shock sag, and rear tire size can affect that measurement quite a bit. But it won't impact the distance from peg to seat.

Well, I didn't want to get into a lengthy conversation, but...

I've started this project by using my AK-1 race bikes as the benchmark since they are a proven design and have won numerous AFM races including a class championship (thanks Zoran!). My AK-1s have a seat height of ~33" and foot peg height (to bottom of peg) of ~14-1/2". These bikes are fairly narrow and foot peg height has been acceptable at that height (no complaints of scrapping from 6 different riders). So that leaves about 18 inches to the seat. Most of my riders have been on the tall side (5'10" or taller) and all have felt the layout was very comfortable. I've never had anyone say that my AK-1 race bikes are too tall although Chris Ulrich rode one for a review in RoadRacing World and commented that the seating position felt "upright". I always attributed his comment to the high bar position that I had chosen to use rather than seat or peg location.

With the new prototype, I'm also at ~33" seat height, but have raised the pegs 1" to ~15-1/2" just to add a bit more clearance (also a fairly narrow chassis). That leaves ~17" to the seat. I've ridden about 600 street miles with the current layout and have been very comfortable (including 500 miles over a 3-day ride). If I were the only person to ride this bike I'd leave everything as-is and call it good.

That said, I have interest from a few folks (including a small race team) who are interested in these new frames. Without knowing who the future riders might be, I just want to make sure I'm not excluding any potential riders by leaving the seat too tall. As mentioned previously, I'm not too worried at this point with peg and bar locations as those are easier to adjust later if needed. Looking at the poll numbers so far, it would seam the sweet spot is somewhere around 31-32" and I'd rather error on too tall than too short for the exact reasons you have mention.

So short answer, I agree with your comments and observations, and believe we're both on the same page. Thanks for the feedback. Much appreciated!:thumbup

 

[stangmx13]

Thnx for the extra info. I get intrigued for sure.

 

[Frame Maker]

Thnx for the extra info. I get intrigued for sure.

I included a link to the complete build thread in my original post ^^^. Would love to have you follow along. I highly encourage more detailed analysis and conversation there.

 

[Sportbiker]

you probably already knew this. Another way to get survey results would be to ask someone how they tall are what was the best road race / supersport bike they ever rode from an ergonomics perspective.
you can then use this website to figure out the actual dimensions.

https://cycle-ergo.com/


Leave it to BARF to make a simple question unnecessarily complicated

 

[Blankpage]

What if the manufactures sold bikes in different frame sizes like bicycles, small medium and large. I’ll take an R1 in a medium please.

 

[Frame Maker]

you probably already knew this. Another way to get survey results would be to ask someone how they tall are what was the best road race / supersport bike they ever rode from an ergonomics perspective.
you can then use this website to figure out the actual dimensions.

https://cycle-ergo.com/


Leave it to BARF to make a simple question unnecessarily complicated

That's a handy website. Just wish it included the actual peg and bar locations, or maybe I need to change the settings? Anyway, thanks for sharing.

Okay, you go first... how tall are you and what's your best fitting sport bike?

What if the manufactures sold bikes in different frame sizes like bicycles, small medium and large. I’ll take an R1 in a medium please.

I'm not sure how practical that would be but interesting idea. Then of course Yamaha build the Morpho and Morpho II concept bikes that articulated to fit different rider positions.

 

[Sportbiker]

5'9" normal proportions of body parts

I've been lucky to have owned quite a few sportbikes.

I'll stick to the last 15 years.. So 2006+ models.

Purely for the race track

1) 2009 R6
2) 2011 CBR1000RR
3) 2008 & 2011 GSXR750
4) 2013 ZX6R

For the street
1) 2011 CBR1000RR
2) 2016 BMW S1000RR

I have not taken my RSV4 to the track yet, but I really believe the RSV4 will be at the top right next to the R6

That's a handy website. Just wish it included the actual peg and bar locations, or maybe I need to change the settings? Anyway, thanks for sharing.

Okay, you go first... how tall are you and what's your best fitting sport bike?

 

[Frame Maker]

5'9" normal proportions of body parts

I've been lucky to have owned quite a few sportbikes.

I'll stick to the last 15 years.. So 2006+ models.

Purely for the race track

1) 2009 R6
2) 2011 CBR1000RR
3) 2008 & 2011 GSXR750
4) 2013 ZX6R

For the street
1) 2011 CBR1000RR
2) 2016 BMW S1000RR

I have not taken my RSV4 to the track yet, but I really believe the RSV4 will be at the top right next to the R6

So going off of the bikes you listed and using the web app, your preference for seat height is clearly in the 32"-33" range. :thumbup

 

[moto-rama]

Even though I am a midget(5'7", 30"inseam) , I prefer a high-ish seat for a supersport type bike, rear sets are nice, too. 32-35" is nice.

My neck, on the other hand is done with race replica and super sport bikes. The years of riding and a couple of surfing injuries have worn those parts out.

When I have a need for something faster than my BMW (31" seat), I like my KtM690, upright bars, high-ish seat, and 320 lbs or so. It takes 45 years off my codgerly carcass.

If you want ground clearance, consider that Overall width is a consideration, not just peg location. And keep your toes on top of your pegs, nothing like getting your foot caught up under a footpeg at high speed.

 

[Frame Maker]

Even though I am a midget(5'7", 30"inseam) , I prefer a high-ish seat for a supersport type bike, rear sets are nice, too. 32-35" is nice.

My neck, on the other hand is done with race replica and super sport bikes. The years of riding and a couple of surfing injuries have worn those parts out.

When I have a need for something faster than my BMW (31" seat), I like my KtM690, upright bars, high-ish seat, and 320 lbs or so. It takes 45 years off my codgerly carcass.

If you want ground clearance, consider that Overall width is a consideration, not just peg location. And keep your toes on top of your pegs, nothing like getting your foot caught up under a footpeg at high speed.

We're on the same page with footpeg location and ground clearance. Thanks for the feedback on the seat height:thumbup