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Setback for Folding Bikes?

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Setback for Folding Bikes?

Old 01-22-13, 07:55 PM
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Tsujigiri00
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Setback for Folding Bikes?

What is the best way to increase the setback for a folding bike (particularly for Terns)? I have long legs and my thighs need additional distance from the pedal crank or else my knees start to bother me.

I assume that changing the seatpost to one with additional setback is not an option (due to the fold). So is the only way to swap the saddle out for one with long rails? Or is it possible to add what seems to be called a "seatpost cap" that has some setback?

(I'm also interested in increasing the height of Tern handlebars and have heard that the Aber Hallo works well for Dahons. Anyone know if they work on Terns as well, despite their different handlebar mechanics/fold? My interest in Terns is due to (A.) currently residing in Chile where the options are limited and (B.) wanting to spend a year or so with a low-mid-range folder before upgrading to a BF or Brompton so that I truly know what I want.)

Thanks for the help. This forum has been a fantastic resource, having just relearned to ride a bike after 18 years off (quit when I got my license at 16).
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Old 01-22-13, 07:59 PM
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While spendy, Bike Friday can make a bike for your frame, as opposed to your being stuck with a one-size-fits-all.
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Old 01-22-13, 08:51 PM
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Originally Posted by Tsujigiri00 View Post
What is the best way to increase the setback for a folding bike (particularly for Terns)? I have long legs and my thighs need additional distance from the pedal crank or else my knees start to bother me.

I assume that changing the seatpost to one with additional setback is not an option (due to the fold). So is the only way to swap the saddle out for one with long rails? Or is it possible to add what seems to be called a "seatpost cap" that has some setback?...
What do mean by "setback"? Do you want to get a higher saddle height so that you get proper leg extension while pedaling or do you feel that your saddle is too far forward above the cranks and you want a way to set your saddle rearward so that the cranks are positioned further in front of you? Those are two different issues to address.

If it's increased leg extension you're after then a longer seat post should do.
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Old 01-22-13, 11:59 PM
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Originally Posted by BassNotBass View Post
What do mean by "setback"? Do you want to get a higher saddle height so that you get proper leg extension while pedaling or do you feel that your saddle is too far forward above the cranks and you want a way to set your saddle rearward so that the cranks are positioned further in front of you? Those are two different issues to address.

If it's increased leg extension you're after then a longer seat post should do.

I mean "setback" in terms of pushing the saddle back further -- straight backwards. (I thought that was the correct term, but perhaps I'm wrong.) I don't need additional seat height: I'm only 6' and Terns (and most folders) accommodate up to 6'4" with seat height (but not necessarily setback and handlebar height).



Originally Posted by alaskanb3arcub View Post
While spendy, Bike Friday can make a bike for your frame, as opposed to your being stuck with a one-size-fits-all.
Thanks, but as mentioned I'm spending some time in Chile and am limited to Tern (and a couple Dahon). I'm not interested in importing a BF for +30% the price, especially since I just relearned to ride after 18 years off and have yet to fully learn my preferences (after which I plan to invest in a BF or Brompton).
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Old 01-23-13, 01:58 AM
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Edit: Have you got the bike yet?

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Old 01-23-13, 02:07 AM
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Brompton's saddle adapter pin on top of a standard seatpost, can be pointed backwards.. then
a saddle clip on it, slides back on what is a 7/8" horizontal tube.

the clip is rotated so the saddle clamps above it.
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Old 01-23-13, 03:06 AM
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The Brompton adapter is not an option, he would have to buy a new seatpost first..

I have an Aber Hallo and using it on a Dahon (think they are close enough to compare) and find it a bit clumsy since you can not release the quickrelease to twist the handlebars when folding. This would also be a problem with the riser MTB bar that BassNotBass mentioned but still a cleaner lighter and cheaper option.


If you manage to find a way to set back the (already long) seatpost you should be concerned about stressing the frame more than it is built for, read about framecracks in a different thread in this forum. Best to buy a bike that fits.
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Old 01-23-13, 03:42 AM
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"This would also be a problem with the riser MTB bar that BassNotBass mentioned"

Me - not BnB.

I edited the post as the OP hasn't told us what the bike actually is.

No, the MTB riser bar on my Speed D7 twists easily in the quick release H/post. Folding is fine but the Dahons fold with the h/bars inside the fold. If anything rubs on the wheel, axle or Magnetix catch the fold width is compromised.

The Aber Hallo is actually an adjustable stem, do you find it traps the QR lever so it cannot be released?

"Best to buy a bike that fits."

Yup. Many 6-footers ride Dahons, Terns and everything else without problems, but not everyone is the same. Try before ya buy. The Terns Handleposts though, are different, some say.

What bike is it going to be?


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Old 01-23-13, 08:08 AM
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The Aber Hallo is actually an adjustable stem, do you find it traps the QR lever so it cannot be released?

Exactely. I like to release the handlebars w the quick release and twist the flatbar so the brake levers are pointed upwards. Gives the best flattest fold. I like the brake leversto be sicking out in front of the bar when riding but that does not give a good fold. W levers UNDER the flatbar it would be a different matter but does anybody ride like that with a flatbar??

And BnB is??? Bed `n Breakfast?
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Old 01-23-13, 08:10 AM
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^^^ BassNotBass

Or Bed N' Breakfast.
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Old 01-23-13, 08:15 AM
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Originally Posted by Tsujigiri00 View Post
What is the best way to increase the setback for a folding bike (particularly for Terns)? I have long legs and my thighs need additional distance from the pedal crank or else my knees start to bother me.

I assume that changing the seatpost to one with additional setback is not an option (due to the fold). So is the only way to swap the saddle out for one with long rails? Or is it possible to add what seems to be called a "seatpost cap" that has some setback?
Doesn't the Dahon/Tern folding bikes with 26" wheels take standard seatposts?

Do the 20" Dahon/Tern bikes use saddles with standard rails? For some reason, I thought that they use something unusual.
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Old 01-23-13, 08:19 AM
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Originally Posted by badmother View Post
... If you manage to find a way to set back the (already long) seatpost you should be concerned about stressing the frame more than it is built for, read about framecracks in a different thread in this forum...
+1.


Originally Posted by badmother View Post
... Best to buy a bike that fits.
The solution.
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Old 01-23-13, 08:21 AM
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Originally Posted by snafu21 View Post
^^^ BassNotBass

Or Bed N' Breakfast.
Ahhh, it was the small N that confused me.

This stem/extender may work, https://www.bikeforums.net/showthread...xtender-advice and bikes are sold with them (but not cheap I think) and I think it is Dahon not Tern. Should be possible to use on Terns also??

Bigger feet, longer legs than avreage is not cheap. That is the price you pay for being tall and handsome!
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Old 01-23-13, 08:22 AM
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Originally Posted by snafu21 View Post
^^^ BassNotBass

Or Bed N' Breakfast.
Are you being snide about my dating practices?
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Old 01-23-13, 08:29 AM
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"Are you being snide about my dating practices?"

No no, makes more sense than a tent in this weather. :-)
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Old 01-23-13, 10:00 AM
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Originally Posted by snafu21 View Post
What bike is it going to be?

I would like to buy a Tern Link D8 when I visit Chile's capital in two weeks. But since I tend to require additional setback, I wanted to find out there was a way to modify the Tern in case it turns out to lack the setback I need. It seems like the answer is "No," or "Not easily." So I guess if the Tern Link D8 is too cramped then I'll have to pass on it and sadly get one of these sketchy Chilean knock-offs.


EDIT: I'm also thinking about getting a Selle Anatomica saddle, which has very long rails that allow for additional setback (and is otherwise fairly similar to a Brooks saddle).

Last edited by Tsujigiri00; 01-23-13 at 11:11 AM.
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Old 01-23-13, 12:07 PM
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Originally Posted by Tsujigiri00 View Post
I would like to buy a Tern Link D8 when I visit Chile's capital in two weeks. But since I tend to require additional setback, I wanted to find out there was a way to modify the Tern in case it turns out to lack the setback I need. It seems like the answer is "No," or "Not easily." So I guess if the Tern Link D8 is too cramped then I'll have to pass on it and sadly get one of these sketchy Chilean knock-offs.


EDIT: I'm also thinking about getting a Selle Anatomica saddle, which has very long rails that allow for additional setback (and is otherwise fairly similar to a Brooks saddle).

selle anatomica saddles are very nice and softer from the get-go than a brooks (but maybe shorter life-span?)
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Old 01-23-13, 12:34 PM
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The Brompton adapter is not an option, he would have to buy a new seatpost first..
OK ,spend the money..

Termonology problem appears.. Definition: Setback is a distance, from a plumb line through the BB
rearward to where you sit, a combination of seat tube angle, and it's length..
and then added to, by seat post design.

changing the handle bars is a separate issue..
Originally Posted by badmother
... Best to buy a bike that fits.




hard to do since other than Bike Friday folding bikes are only made in 1 size..

Last edited by fietsbob; 01-23-13 at 12:40 PM.
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Old 01-23-13, 12:43 PM
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Originally Posted by fietsbob View Post
OK ,spend the money..

Termonology problem appears.. Definition: Setback is a distance, from a plumb line through the BB
rearward to where you sit, a combination of seat tube angle, and it's length..
and then added to, by seat post design.

changing the handle bars is a separate issue..
Definition, absolutely. Creating a further setback is going to do a lot more to ridingposition power transfer and "feel" of the bike. I think maybe the OP fear a cramped cockpit more than not enough setback, and wanting to set the saddle back is the solution he think is the best. Since folders already have more % of the riders weight on the rear wheel than regular bikes I would suggest looking at solutions around the stem instead. Just sayin.



And:
Originally Posted by BassNotBass View Post
Are you being snide about my dating practices?
If in doubt take it as a copliment- always!

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Old 01-23-13, 12:49 PM
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Originally Posted by badmother View Post
Definition, absolutely. Creating a further setback is going to do a lot more to ridingposition power transfer and "feel" of the bike. I think maybe the OP fear a cramped cockpit more than not enough setback, and wanting to set the saddle back is the solution he think is the best. Since folders already have more % of the riders weight on the rear wheel than regular bikes I would suggest looking at solutions around the stem instead. Just sayin.

+1 just agreein'

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Old 01-23-13, 02:37 PM
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Originally Posted by badmother View Post
...Creating a further setback is going to do a lot more to ridingposition power transfer and "feel" of the bike. I think maybe the OP fear a cramped cockpit more than not enough setback, and wanting to set the saddle back is the solution he think is the best. Since folders already have more % of the riders weight on the rear wheel than regular bikes I would suggest looking at solutions around the stem instead. Just sayin...
Agreed wholeheartedly. But I'm still struggling with understanding the thigh clearance and knee pain concern.
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Old 01-23-13, 02:43 PM
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OP:' I'm also thinking about getting a Selle Anatomica saddle'

Oh, the SDG Bel-Air saddles also have long(er) rails and a flip-up rear section. I have one on my Mezzo and another on my Dahon Jack.
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Old 01-23-13, 03:39 PM
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Originally Posted by badmother View Post
I think maybe the OP fear a cramped cockpit more than not enough setback, and wanting to set the saddle back is the solution he think is the best. Since folders already have more % of the riders weight on the rear wheel than regular bikes I would suggest looking at solutions around the stem instead. Just sayin.

You are mistaken about this. I (the OP) am concerned about having enough setback and do not fear a cramped cockpit; for my size and body shape, adequate setback is the #1 factor that determines whether I can efficiently ride a specific bike. For example, I've tried almost a dozen friends' bikes in the last two months. And over half of them only worked well when I hung my butt over the back of the saddle (note that I'm 6', but these friends are Chilean and tend to be 5'6"-5'9"). It's the same problem I have with gyms' stationary bikes: I can't use them if they do not have a saddle slider for adjusting setback.

Cramped cockpit is the least of my concerns because I prefer an upright riding position (and a cramped cockpit actually helps provide this, as long as the handlebars are the correct height).
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Old 01-23-13, 03:57 PM
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According to this the tern post diameter is 33.9.

https://www.ternbicycles.com/us/forum/seat-post-size

Here is a Woodman topper designed for integrated seat masts that's available in 33.9

https://www.woodmancomponents.com/Web...%88%2005:46:21

So, provided you are already not at the post's maximum extension and have a few cm to play with, hack off the end of the stock post and install the topper and saddle.

If you don't want to alter the stock post you could always buy another in the appropriate diameter and do the same. Here's a 33.9 on ebay for $25 + ship.

https://www.ebay.com/itm/New-TOTTA-SP...-/150604266924

A longer railed saddle like a Fizik Arione or Tundra might also work to get you the setback you need. Here's a side view of a Tundra. Long rails are long.

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Old 01-23-13, 04:00 PM
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If I understand correctly, the problem is the position of the saddle relative to the position of the pedals. The discomfort probably comes not at the bottom of the pedal stroke but at the 3 o'clock position or through the power stroke and your preference is to be further behind the pedals to get better comfort. If this is the case, it might be an option to consider swapping out the crankset for one with longer arms. This would effectively decrease your seat tube angle and get you farther away from the pedals through the power portion of the stroke. The question would be whether you can get cranks long enough to get you back as far as you would like to go and the crank lengths aren't adjustable so you have to be pretty sure of what you want.

I have the opposite problem in that I find that a lot of folders put the saddle too far back for me. When the frames have the seat tube coming up from behind the bottom bracket shell rather than centered on it, the effective seat tube angles are less steep. I'm always looking for ways to get my knees farther forward on the power stroke. Going from 170mm to 165mm cranks on one of my folders helped and I will try the same for the next one as well.

The Tern Link D8 appears to be one of the folders with the seat tube behind the bottom bracket shell. If you haven't tried one yet, you might find it fits you better than you expect.

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