Suspension seatposts question asked by oldie

danfoto

Esteemed Pedelecer
Dec 2, 2010
405
36
Sarfeast England
My dear wife is 60 years old and has been riding bikes all her adult life. She is generally fit and certainly not fat, but has some arthritis in her right hip. This doesn't really affect her riding (yet), but from time to time she suffers from flare-ups of tendinopathy and ischial bursitis. Put simply, this causes her a really unpleasant pain under/near her right sit-bone.

She currently rides a Batavus Ego which has a very relaxed upright riding position, though it's not quite the classic Dutch bike "sit up and beg". This of course results in her putting more pressure on her sit-bones than when she's riding her Thorn Sherpa which has a rather more "aggressive" riding position. After much experimentation we've finally found a saddle that she's comfortable on for more than a couple of miles (Ergon ST Women), but I'm now wondering about maybe getting her a suspension seatpost in view of all the potholes in the roads hereabouts.

Problem is I know nothing about sprung seatposts. I suspect that much like suspension forks it's a matter of the more you spend the more benefit you get, but is there any particular model which might improve matters for my wife? Please bear in mind that this is for a 60 year old woman with sit-bone issues, an upright riding position and for everyday use on roads only.
 

shed

Pedelecer
Mar 6, 2021
29
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In the "not too ludicrous" price range the Suntour SP12 NCX at around £52 seems to get a lot of praise from various reviews from differing categories and weights of bike riders that I've seen (no direct experience of it myself though).
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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Basildon
The only type worth getting are the parallelogram type, like the Suntour NCX or Thudbuster.
When I tried a demo bike with the NCX, I literally thought I was riding a full suspension bike. I was so impressed by it, that as soon as I got off the bike, I looked at the frame to see what type of shock unit was in the frame so that I could get one for my bike, then got really confused when I saw that it was a hardtail bike
 
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sjpt

Esteemed Pedelecer
Jun 8, 2018
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Winchester
Another vote for the Suntour SP12, we've got one on the back of the tandem (back seat of a tandem can be rather harsh) and my wife loves it. I transfer it to our non-electric solo when I take that out, I love it too.
 
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Simon Knight

Pedelecer
Aug 19, 2009
49
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Hi,
While expensive I have found the Redshift Shockstop to be really effective. It looks good as well. Only available in 27.2mm size so may not fit or will require shims.
 
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Jodel

Pedelecer
Oct 9, 2020
172
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Another endorsement of the Suntour SP 12 NCX. My partner (same age as your wife) has one on the back of our tandem and she wouldn't be without it. They are very good indeed for the money.
 
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danfoto

Esteemed Pedelecer
Dec 2, 2010
405
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Sarfeast England
Thanks very much indeed one and all :)

Right then, before I order a "Suntour SP 12 NCX 31.6 x 350" for her ladyship, can I just ask if I'm right that it should fit OK? Existing seat post is 27.2mm diameter and there is exactly 150mm between the top of the seat tube and the underside of her saddle rails.

Are we good to go?

ETA - It looks to me like the wife's saddle would end up considerably further back than it is now with the standard seatpost, because the clamps on the Suntour aren't in line with the seatpost axis. Am I missing something obvious here?
 
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davell

Pedelecer
Jun 6, 2017
154
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Doncaster
The saddle will be further back but you may be able to compensate to a degree by clamping further back on the saddle rails.
 

Jodel

Pedelecer
Oct 9, 2020
172
135
No - if your seatpost diameter is 27.2, that's the size of NCX you'd have to order, 31.6 is measurement of the seatpost diameter and is too big to fit her bike.

The other measurement is the length of the seatpost - either 350mm or 400m sizes are available. We have a 27.2 x 400 on the back of our tandem. We needed the 400mm length because the back of our tandem has a low step over height so the seat-tube is quite short and we needed the longer size seatpost.

On a normal solo, the 350mm length is probably ok - but check that it will fit far enough down into the frame and that you'll still leave a sufficient length of seatpost in the frame when adjusted to the correct height.

The 'setback' on the Suntour seatpost is 25mm - that may or may not be an issue depending on where your wife currently has her saddle positioned on her existing seatpost. Some seatposts are in-line, others (like the Suntour) have some setback. You'd need to check that you have sufficient length on the saddle rails to accommodate any required shift in fore / aft position. BTW: You can't 'cheat' and fit the seatpost back to front to overcome this.

The attached manual might help.
 

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danfoto

Esteemed Pedelecer
Dec 2, 2010
405
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Sarfeast England
Much obliged, jodel. Oh poo. That seems to be a non-starter on account of the "set back" but we'll check again tomorrow.

Point noted about diameter, btw.
 

Jodel

Pedelecer
Oct 9, 2020
172
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You may be OK regarding the setback as most seatposts normally have some setback - the in-line seatposts are less common.

As it happens, our tandem has an in-line post on the front and a Suntour NCX on the back so you may be able to see the difference:

ebike.jpg
 
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Gringo

Esteemed Pedelecer
Jun 18, 2013
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Northampton
Is this your bike? This bike has a totally different clamp arrangement to most modern bikes but the clamp area is setback anyway
B56891DE-BF29-4CAE-88D3-F98B277DF615.jpeg
if it is you won’t have any offset problems with the ncx post
 
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danfoto

Esteemed Pedelecer
Dec 2, 2010
405
36
Sarfeast England
Thanks for that, jodel. I see what you mean. We'll definitely have a good think about this aspect tomorrow.

What's your thoughts on the spring, given that my dear wife is currently 63Kg but determined to get back to 60 before much longer?

Having checked the manual to which you kindly linked above, I see that the soft spring is the one we'd want.

And what I hope will be my final question - what exactly is the point of the optional sleeve thingy that goes over the linkage?
 
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danfoto

Esteemed Pedelecer
Dec 2, 2010
405
36
Sarfeast England
Is this your bike? This bike has a totally different clamp arrangement to most modern bikes but the clamp area is setback anyway
View attachment 41590
if it is you won’t have any offset problems with the ncx post
Nope, not that one. It's the one on this page ...

Funnily enough, there seems to be more set back in that picture than on Ann's bike, but it's chained up in the shed for the night now so I can't be sure until the morning.
 

Nellie

Pedelecer
Jun 15, 2020
46
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The cover or sleeve I’ve been told is for 2 reasons 1. To stop oil or grease from mechanism getting on anything else which I think is a maybe. Or 2. To stop contaminants getting in mechanism which would be mud and grit when used with off road mountain biking. I think that’s the more likely reason. But who knows.
 
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Jodel

Pedelecer
Oct 9, 2020
172
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My partner is also 60Kg and the standard spring at the minimum pre-load setting works fine for her. I couldn't get a soft spring a the time we bought our seatpost, but she's perfectly happy to keep using the standard spring as it takes away a lot of the road shock.

The sleeve is just a neoprene cover to keep the mechanism free from dust / grit and so on. It was an optional extra that we bought with the seatpost - probably aimed more at off-road riders.
 
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richtea99

Esteemed Pedelecer
May 8, 2020
440
283
I also have a Suntour SP 12 NCX (after recommendations here - thanks all!). My only minor criticism is that it doesn't seem to have any rebound damping - you hit a hole/bump and you bounce down, and then back up again at about the same rate. Which is better than a hard whack, but not as sophiscated as full suspension, etc. But it's a good compromise - less weight, less cost, easy fitting.

The neoprene cover for it also makes it less interesting to steal (a single allen key loosened and you've lost £50 or more). Covers can be found on eBay for about £4:
 
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danfoto

Esteemed Pedelecer
Dec 2, 2010
405
36
Sarfeast England
... a single allen key loosened and you've lost £50 or more ...
That's a good point. If we do get one of these seatposts, I'll certainly see if I can get hold of a replacement bolt with a security head. Maybe pin hex ...