Fancy seatpost for more saddle angle adjustment?

[6zfshdb]

An older post, but if you're looking to get a greater range of seat angle adjustment, you might try one of these:

https://www.amazon.com/dp/B088R7BLB3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

Not very well reviewed, but I've been using them on my bikes and haven't busted one yet. The trick is to shorten it so the strain is as close to the bend as possible. This also eliminates the spring action.

It's also useful for adjusting the seat post offset.

 

[fexixav]

I'm relatively new to the bike world and I'm surprised how much there is to learn about basic bike geometry. Today's challenge is my wife's seat post on her Electra ebike. Her combination of seat tube angle, seat post design, and desired saddle angle are the issue. Her saddle adjustment is of the "two bolt" variety, with one forward and one aft bolt as shown below (this is a google image, not her seat post). In order to adjust her saddle angle to her liking I had to put a shim between the cylindrical mating surfaces in the seat post - only then could I adjust her saddle nose low enough for her. The geometry at the head of the seat post seems to be the issue:

View attachment 198371

Specifically, the angle shown in red seems to be working against me here. When I "middle" the two bolts, i.e. set the saddle angle at the center of the adjustment range, the nose of the saddle points up at a ~10 degree angle. When I fully loosen the rear bolt, and fully tighten the front bolt, i.e. set it to the extreme nose-down end of the adjustment range, the saddle is about horizontal - but she wants the nose down ever-so-slightly more. To accomplish this, I inserted an aluminum shim, and that did the trick - it added just enough additional range, that she is happy. However, I am not so happy to have a shim here - I would rather have a seat post that does not require a shim.

When reading about seat posts, I see the specifications given for length, minimum insertion, and offset, but I never see specs for the angle shown in red above. I would think, ideally, the red angle here should be complimentary to the seat tube angle on the bike - i.e. if the bike has a 57 degree seat tube, this red angle should be 33 degrees (57 + 33 = 90, the definition of "complimentary"). Maybe bikes in general don't vary in seat tube angle that much, so this just usually isn't important?

I'm wondering if anybody else has faced this, and if there are "two bolt" seat posts that might offer a larger range of adjustment than hers, or if there are other seat post designs that might accommodate a larger range of adjustment? I did try a serrated one-bolt design, which did seem to have more adjustment range, but the stepped nature didn't allow me to dial it in exactly.

I also saw somewhere a seat post that offered an eccentric bolt for the saddle angle adjustment, similar to how options for breast augmentation NYC provide precise customization, but I can't find it now—has anybody seen one of these before?

TIA!

Two-bolt seat posts have a limited adjustment range, and the “red angle” isn’t usually specified because most are designed for standard seat tube angles. For bikes with unusual angles or precise nose-down preferences, options are a post with a wider adjustment range, a one-bolt micro-adjustable post, or using a shim. Some rare posts have an eccentric bolt for fine saddle angle adjustment, mostly in triathlon/TT models.

 

[Base]

I do not know any single bolt clampen seat post that actually is approved with a clinical test for use in a EN15490 normed bike (E-bike). I've seen plenty of tests and they all fail dramatically. I would not suggest to use such a SP on an E-bike.

SP tests are done in house and at EFBE or Dekra

 

[spokewrench]

An older post, but if you're looking to get a greater range of seat angle adjustment, you might try one of these:

https://www.amazon.com/dp/B088R7BLB3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

Not very well reviewed, but I've been using them on my bikes and haven't busted one yet. The trick is to shorten it so the strain is as close to the bend as possible. This also eliminates the spring action.

It's also useful for adjusting the seat post offset.

Sold! Some of those who complained that it broke submitted photos showing the seat clamped out at the end. The manufacturer says that's for 20kg riders.

One of my bikes has the saddle tipped forward at 18.5 degrees, as far as I could get it. On my other bike, it's only 15.8. This device should let me tip them forward as far as feels right, besides allowing a bit of fore-and-aft adjustment.

I start a power stroke at TDC, which means I'm kicking the pedal forward. A saddle needs to be tipped forward to brace me against the thrust; otherwise I'd have to pull back on the bars. Two other benefits are that only my sit bones press the saddle, and it's easy to slide forward and down when I stop, and backward and up when I get underway.

 

[stompandgo]

I fitted a guy last week who came in with his saddle tipped down about 20 degrees. He had one of those steerer extender things on top of several spacers, and drop bars. Fortunately, the steerer was not cut. He ended up with a proper width flat saddle with a cutout mounted level, no steerer extender, more spacers, and a Zipp 25 degree stem flipped up. He said it's like riding a new bike. He felt that he had a lot more power. He did, because we rotated his hips forward so that he was pedaling more efficiently.

 

[jabberwocky]

I fitted a guy last week who came in with his saddle tipped down about 20 degrees. He had one of those steerer extender things on top of several spacers, and drop bars. Fortunately, the steerer was not cut. He ended up with a proper width flat saddle with a cutout mounted level, no steerer extender, more spacers, and a Zipp 25 degree stem flipped up. He said it's like riding a new bike. He felt that he had a lot more power. He did, because we rotated his hips forward so that he was pedaling more efficiently.

Ebikes can really hide a lot of crimes, bike-fit wise. I've seen some truly bizarre saddle/stem decisions made by ebike riders. Its easier to get away with when the motor is doing a lot of the work. But man, a bike that fits properly and has a saddle that works for you is just so much nicer to ride.

 

[stompandgo]

I fitted a guy last week who came in with his saddle tipped down about 20 degrees. He had one of those steerer extender things on top of several spacers, and drop bars. Fortunately, the steerer was not cut. He ended up with a proper width flat saddle with a cutout mounted level, no steerer extender, more spacers, and a Zipp 25 degree stem flipped up. He said it's like riding a new bike. He felt that he had a lot more power. He did, because we rotated his hips forward so that he was pedaling more efficiently.

This customer came into the shop yesterday to thank myself and the lead fitter for our work. He rides in the drops all the time now. He was out for a ride with friends and they had to tell him to slow down. He also said that he had zero pain afterwards, when he used to write off the pain as part of riding.

 

[fritz katzenjammer]

the original issue doesn’t sound right at all. The seat provided with the Electra is of a type usually fitted with the nose up a bit, sorta nestles yer bum into the wide bit at the back of the seat. Is the seat post the right way around, I’ve seen dopier things done by shop builders. The portion with the pivot is to the rear of the seatpost on the Electra post. ( to the right below )

OR.. is the bike in question an Electra Loft? The seat that comes with those is terrible and should be replaced with the type fitted to the regular Electra bikes. The engineer who specified that seat should be made to ride on one for as long as the battery lasts… that’ll learn ’em.

 

[GMA52]

I put a Saffort Seat post on my bike. It is nicely made but the first one would not adjust below 125kg. I have another coming today. Hoping it works well and will let you know.

https://www.amazon.com/sspa/click?ie=UTF8&spc=MTo2Njg3NTU2Mjk1MDIzNDY5OjE3NjIzODE5OTY6c3BfYXRmOjMwMDg2MDA2MDMxNTUwMjo6MDo6&url=%2FSAFORTBIKES-Suspension-Seatpost-eBike-Riders%2Fdp%2FB0F6C95J57%2Fref%3Dsr_1_5_sspa%3Fdib%3DeyJ2IjoiMSJ9.-pergbUp47HLFc46ba_kEEfeQDWrqGjUHhiyXEmiOYMcua8mCAzynzEpbYYuTikaH-tI7QStRF7Yd5E4vPwr4aKq_kGcLVyWrDQG--YDkY_hYFEcdnhTqkioT7-vuUna1KXw9T10ZxJ2Fcy4k6-yGND8Gt1Lu_wf3K8fgAynJomb1KVZDNXoEAHEgpX-u_-yW11hutWvpmsU2i3cxpMSswjoIXuR7gvkgeEZ1zblaPxVxh1uLWi8fXDm4OXXH0bdmwZ_QCdUpLO55WMxWICQ_H9Sh1zlQKg8dl1Aom-Phxo.P73fo0MU3URiraJM7Qw2RlbdHzhfLLOeIbZTGXrZ2-c%26dib_tag%3Dse%26hvadid%3D634485671683%26hvdev%3Dc%26hvexpln%3D0%26hvlocphy%3D9027214%26hvnetw%3Dg%26hvocijid%3D12540596370642688200--%26hvqmt%3Db%26hvrand%3D12540596370642688200%26hvtargid%3Dkwd-360754217160%26hydadcr%3D2427_13557951%26keywords%3Dbest%2Bsuspension%2Bseat%2Bpost%26mcid%3D54b26d6d8acd3e4590c54344d68bbde8%26qid%3D1762381996%26sr%3D8-5-spons%26sp_csd%3Dd2lkZ2V0TmFtZT1zcF9hdGY%26psc%3D1

 

[efair]

Thanks for all the great responses. To answer the question: I've left the shim in place, it has not loosened again in 250 miles, the rider is happy - so it will stay. Her seat is the factory seat, not "Loft". And her post is in the correct orientation (I tried it both ways - turning it backwards compounds the problem).

Slightly OT but I can agree with "hides a lot of crimes" above. Not that I think her bike is criminally unfitted, but the motor does afford much leeway. Honestly, my Gazelle is the worse offender, but it's complicated by my L2/L3 disc and my need for extension (vs inflection) to avoid lumbar pain the next day.

 

[efair]

I do not know any single bolt clampen seat post that actually is approved with a clinical test for use in a EN15490 normed bike (E-bike). I've seen plenty of tests and they all fail dramatically. I would not suggest to use such a SP on an E-bike.

SP tests are done in house and at EFBE or Dekra

Just so that I can make informed decisions, how did the single bolt SP tests you've seen fail? My daughters Aventon hads a single bolt post (and, surprise, gives her trouble).

 

[spokewrench]

He said it's like riding a new bike. He felt that he had a lot more power. He did, because we rotated his hips forward so that he was pedaling more efficiently.

I guess a road biker tries to have his spine horizontal at the shoulder blades. If he didn’t tilt his pelvis at all, he’d have to arch his back 90 degrees, squeezing his heart, lungs, and other organs.

Maybe I can figure out how to set up a camera so I can measure how far I lean forward and how far my belt line tilts forward. I seem to lean forward about 30 degrees (which a road biker would call upright). My spine seems to be straight, which implies that I tilt my pelvis forward about 30 degrees. I had my saddle tipped at 16 degrees. My new adapter let me tip it to 28 degrees. It’s much more comfortable because the seat’s padding aligns more squarely with my sit bones.

I remember how great my Raleigh felt, 60 to 70 years ago, before bikes with that geometry went out of fashion. Suddenly my Abound feels like that: more comfort, more climbing power, and less fatigue. With the Raleigh seat, I sat on longitudinal coil springs covered with horsehair padding. I didn’t tilt the seat forward more than 10 degrees, but maybe the springs accommodated a range of pelvic tilts.

Page 63 of the 2013 edition of Phil Burt’s “Bike Fit” says that the Union Cycliste Internationale had a new regulation that seats had to be flat, and a 1 degree tilt could disqualify a rider. He said that innovators like Chris Boardman and Graeme Obree had demonstrated such big advantages with a forward tilt that the UCI treated it as unfair. Burt said a tilted seat lets you move the pressure point to your sit bones. It lets you lean way over with a straighter spine, It increases power by letting glutes perform better.

According to the 2025 rules, the UCI will now allow a tilt of 9 degrees. For a road bike, that sounds radical because a rider’s position doesn’t seem to brace him against sliding forward.

The back of my seat is 30 inches behind my hand grips. That’s the typical width of a bedroom doorway. Suppose I stand in the middle, facing one side of the frame. Suppose a bicycle seat is attached to the frame behind me at such a hight that if I stick my butt back and flex my knees slightly, I’ll be lightly resting on it. Most of my weight will be on my feet, but the seat will stabilize me. Suppose there’s a “handlebar” across the frame in front of me at belt level. (Belt level for someone perched on a bicycle seat is higher than if he were on the ground.) Now my hands and butt will stabilize me with a triangle. It doesn't feel at all stable to me on a bike with low bars and a forward seat.

For an experiment, I took my feet off the pedals. There was far more weight on my arms than normal. That proved to me that I keep most of my weight on my legs all the time, as in skating.

 

[stompandgo]

You can fit proper hip rotation without flattening the back to World Tour proportions. It's about reaching a neutral position on the bike, where you are riding the bike, and the bike is not riding you.

 

[spokewrench]

I had to look up "neutral position." Burt says it's his fit window within which personal adjustments can be made for adaptive fitting. He also says adaptive fitting might require going outside his neutral position.

In 2020 I bought a Radrunner mostly because if an EBR review. The reviewer was about my height, as was a Radpower employee who rode with him. The reviewer talked about how stable it was. I took their demonstration to mean I'd be in a neutral position. In fact, it was so unstable that I couldn't always stay on the pavement if I attempted a slow u-turn on an 18-foot roadway. Bumpy pavement made it so hard to control that I got tennis elbow in my right arm from fighting for control when I lifted my left hand to signal. I recalled that in the video, when they discovered they needed to make a u-turn on an empty street, the video had cut and resumed after they were again going straight on smooth pavement.l

After a week I put a convex bike mirror on the end of the handlebar. I heard a car right behind me. I studied the mirror but couldn't see it. Turning my head on such an unstable bike would have been very dangerous. When it passed, I saw that it was the same color as the pavement, and the afternoon was overcast. I rode straight home and threw that mirror away.

The seat was almost over the pedals, so pedal pressure couldn't brace me against lurching on each bump. The bars were my only brace. If I hit bumpy pavement with only one hand on the bar, it took a strong twist to keep my inertia from steering the bike out from under me. With both hands on the bars, my arms and spine formed a sort of tripod to stabilize my upper body. A u-turn subjected me to rapidly changing inertial forces, and with such a short base, my support tripod wasn't very stable. With a layback seat post, I got my seat several inches farther behind the pedals and the handlebars. I now had the control to make a u-turn on a 10-foot driveway, and my tennis elbow healed.

 

[stompandgo]

Whatever floats your boat. If this works for you, great. When it doesn't, get a proper fit. It may help your riding experience.