How to improve ride quality?

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How to improve ride quality?

Postby Scooterman » 17 Oct 2019, 19:56

My chair has a effing harsh ride on the narrow undulating UK pavements dug up to install cable tv, tree roots, etc, At anything above 3 leds on the r-net it's a jolting ride. Roads are fine at 5 leds as they're smoother.

I can't do anything about the front wheels which are 9" mobility scooter pneumatic tyres. 9" is the largest dia that will fit in forks, plus 10" wheels would mean having to find 10" forks and moving the seat forward which I don't want to do.

So I've only got the rear end to play with.

About 18 months ago I removed about 50kg from the top half of the chair. Recently I've been looking on eBay for a used pair of shocks with lower spring poundage rating. Front mobility scooter shocks look to most promising.

But whatever I find the shock units are short with little travel so I can't imagine are ever going to be that good at cushioning out the jolts?

It's the jolts that are the killer and make using the chair at speed or for any length of time outdoors fatiguing.

So I was thinking of balloon rear tyres on new rims? Do balloon tyres improve the ride much?

Any suggestions/experience of what works?
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Re: How to improve ride quality?

Postby Burgerman » 17 Oct 2019, 20:28

Realistically theres little you can do. Low pressure tyres with large section helps. But not massively.
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Re: How to improve ride quality?

Postby Scooterman » 17 Oct 2019, 20:42

Burgerman wrote:Realistically theres little you can do. Low pressure tyres with large section helps. But not massively.

Mmmm that's does help, I like honest advice :thumbup: . The set-up of the chair is perfect for me at the moment so I wouldn't want to go to the expense and hassle of messing around with it for not much gain.

I wonder partly because me and the chair are so lightweight that the chair gets jolted around, and powerchairs have a short wheelbase?

I measured the wheelbase of the salsa and compared it to my scooter (which has a better ride quality), and the powerchair WB is exactly half the WB of the scooter.

Perhaps I'll just have to live with it. It's okay as long as I don't go everywhere at 6mph.
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Re: How to improve ride quality?

Postby steves1977uk » 17 Oct 2019, 22:56

Have you tried lowering tyre pressure SM? Say 5-10 psi for the casters and 10-15 psi for the rear wheels. That will give a softer ride but use more power. I use 20 psi all round but the seat on my chair is sprung, so that absorbs any nasty bumps.

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Re: How to improve ride quality?

Postby shirley_hkg » 18 Oct 2019, 01:52

I'd definitely try 3.50-8 tyres first @25 psi or lower.

This is the easiest and foolproof, at the lowest cost as well.
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Re: How to improve ride quality?

Postby rickystyx » 18 Oct 2019, 10:43

Just wondering if something could be rigged up between the frame and the seat plate as secondary suspension. When I was able to use my bike I had a suspension unit between the frame and the saddle - it made a massive difference on rough tracks - so I was thinking that perhaps one mounted either side between the frame and the seat plate may work but the front of the seat plate would have to be hinged in some way.
Just a thought
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Re: How to improve ride quality?

Postby wheelie junkie » 18 Oct 2019, 11:38

I use a chin control so you can imagine how difficult steering is on UK pavement. Went to Tate Liverpool a few weeks ago in the Albert Dock, miles of cobbled pavement and felt like I had been in a boxing ring for 10 rounds. That was with 120/70 tubeless rear tyres and air filled casters plus 4 wheel suspension with soft springs. They all help make a difference but you still get battered. Soft springs can help but ride becomes choppy, brake hard and front compresses then squats back as you accelerate and has side to side movement. I wouldn't revert the changes I made but don't expect miracles.
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Re: How to improve ride quality?

Postby Scooterman » 18 Oct 2019, 11:49

steves1977uk wrote:Have you tried lowering tyre pressure SM? Say 5-10 psi for the casters and 10-15 psi for the rear wheels. That will give a softer ride but use more power. I use 20 psi all round but the seat on my chair is sprung, so that absorbs any nasty bumps.

Steve

I will give that a go first Steve, I'm not sure what PSI I'm running. I use a hand pump and just pump them till feel firm :oops:

shirley_hkg wrote: I'd definitely try 3.50-8 tyres first @25 psi or lower.

This is the easiest and foolproof, at the lowest cost as well.

I think I'll definitely end up going down the road of the tyre size you suggest. The rubber on the existing tyres seems quite stiff with not a lot of flex?

rickystyx wrote:Just wondering if something could be rigged up between the frame and the seat plate as secondary suspension. When I was able to use my bike I had a suspension unit between the frame and the saddle - it made a massive difference on rough tracks - so I was thinking that perhaps one mounted either side between the frame and the seat plate may work but the front of the seat plate would have to be hinged in some way.
Just a thought

I've seen lots of MTBs with seat suspension. I was always dubious whether it helped or was just gimicky and adding weight. But your experience says otherwise :thumbup:
But fitting suspension between the seat and frame of a powerchair is way beyond my DIY abilities, plus I think it would raise the seat too high :eh:

A mob dealer has these scooter shocks in stocks which are 100 lb/in less than my chair's shocks. But I need to check the dimensions :problem:
Screenshot 2019-10-18 at 11.43.12.png
Screenshot 2019-10-18 at 11.43.12.png (152.84 KiB) Viewed 480 times


Also I've found this spring supplier which is a cheaper option. But whether I can find a coil spring to match the existing spring dimensions???
https://www.ashfield-springs.com/shop/c ... ngs-3-10mm

I think 7 n/mm equals 40 lb/in

Btw does anyone know how manufacturers of WCs, mob scooters, cars, vans, etc, calculate what lb/in of spring rating to fit?
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Re: How to improve ride quality?

Postby Scooterman » 18 Oct 2019, 12:13

wheelie junkie wrote:I use a chin control so you can imagine how difficult steering is on UK pavement. Went to Tate Liverpool a few weeks ago in the Albert Dock, miles of cobbled pavement and felt like I had been in a boxing ring for 10 rounds. That was with 120/70 tubeless rear tyres and air filled casters plus 4 wheel suspension with soft springs. They all help make a difference but you still get battered. Soft springs can help but ride becomes choppy, brake hard and front compresses then squats back as you accelerate and has side to side movement. I wouldn't revert the changes I made but don't expect miracles.

Thank you Wheelie, you make some really good points. Your experience is much appreciated :thumbup:
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Re: How to improve ride quality?

Postby steves1977uk » 18 Oct 2019, 13:06

I use one of these... https://www.airman-uk.com/product/airgun-compressor/ Soon inflates tyres to the specified PSI you set. :thumbup:

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Re: How to improve ride quality?

Postby shirley_hkg » 18 Oct 2019, 14:15

I use this naked parts @£1.25 , with 50psi gauge. cheers
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Re: How to improve ride quality?

Postby hank » 18 Oct 2019, 14:18

Gas air shocks would work better if could fit some in. ;)
Quickie groove Brushless
BM2.5 clone
Foldawheel PW 1000 XL.
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Re: How to improve ride quality?

Postby shirley_hkg » 18 Oct 2019, 14:48

All these can do away cracks and holes of pavement only , but Not the back and forth rocking .

Scooterman himself has pointed out the reason already , short wheelbase and seat high.

Articulated caster arm with suspension like Storm 4 Xplore / Willchair 123 etc , may help.
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Re: How to improve ride quality?

Postby wheelie junkie » 18 Oct 2019, 17:54

Most mountain bikes don't have suspension seatposts what is common is a hydraulic dropper seatpost not suspension. Air shocks have a downside in the amount of friction caused by the seal and relatively big diameter shaft. I work in mountain bike industry and have access to both coil and air shocks, fitted air to my off road chair and because of the suspension design with a low leverage ratio the shock pressure was low and difficult to overcome initial seal stiction. You really need to understand leverage ratio and progression before trying to design a suspension system.

It is easy to adjust air rather than having to find the right coil spring but also easy to be outside the optimum operating pressure.
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Re: How to improve ride quality?

Postby White Lightnin' » 18 Oct 2019, 18:58

Use spoked wheels with multiple cross lacing to soften the ride.
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Re: How to improve ride quality?

Postby farmer » 19 Oct 2019, 00:29

get a 1/2in. or whatever mm that is equal to the size of your cushion and put a scooters tube with a little air in it between the board and base put your cushion on and have at it , to soft add more air to hard take some out
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Re: How to improve ride quality?

Postby Scooterman » 21 Oct 2019, 14:16

White Lightnin' wrote:Use spoked wheels with multiple cross lacing to soften the ride.

Do spoked wheels temporarily deform when they hit a bump and give a cushioning effect?

My manual wheelchair has 24" spoked wheels and thin slick HP tyres that I pump up to 120psi, although they probably sit around 90-100psi most of the time. Even though you'd think that would give a hard ride they're actually quite cushioning. And the thin plywood seat base flexes a bit as well.

The solid 4" front castors are a different matter though, and are lethal outdoors if you don't keep your eyes peeled for debris, especially in the autumn.
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Re: How to improve ride quality?

Postby Burgerman » 21 Oct 2019, 19:49

Spoked wheels dont change anything. Unless the spokes are loose! And then it will destroy itself.
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Re: How to improve ride quality?

Postby Scooterman » 21 Oct 2019, 19:53

Burgerman wrote:Spoked wheels dont change anything. Unless the spokes are loose! And then it will destroy itself.

:thumbup:

I thought they might flex a bit, boing!
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