Classic British SparesKlempf British PartsBaxter CycleBritBike Sponsor SteadfastCyclesSRM EngineeringLucas Classic MotorcycleHepolite PistonsIndustrial tec supply

Upgrade your membership to: Premium Membership | Gold Membership | Life Membership | Vendor Membership | Site Sponsor Membership
Welcome to BritBike Forum!
Britbike forum logo
Member Spotlight
MikeJ
MikeJ
San Mateo, CA USA
Posts: 32
Joined: March 2017
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Thread Like Summary
Gordon Gray
Total Likes: 6
Original Post (Thread Starter)
#823179 09/10/2020 3:04 PM
by dave jones
dave jones
How good are gel pads for helping with a hard seat? Also, can they cope if the suspension bottoms out on a pot hole? Sometimes it feels like my spine is being compressed to half the length on pot holes at speed (not literally, of course!). I thought of softer springs but maybe the shocks would bottom out or maybe they are already. I am very light at 7 1/4 stone. I wonder if this fact makes the ride rougher. Not sure how to proceed on this.

I can't remember the make of my shocks but they are Girling copies. NJB, possibly. I probably have the receipt still from a few years back. The ones I bought were the right ones for my bike which is a 1967 Triumph 650.

Dave
Liked Replies
#823350 Sep 11th a 03:11 PM
by dave jones
dave jones
Thanks, Gordon. Not sure if they are bottoming out but there can be a big jolt. I normally keep an eye out for obvious pot holes and lift myself up if I can't steer round. I think one thing I will have to do from now on is to slow down a bit!

Lannis- I may still look into the gel seat just for the bones and prefer the idea of it hidden in the seat to preserve the look.

Also, many thanks to Laurence, Bill, Anglobike, Ed, Mark and David.

I did have another thread where I asked about seat foam a couple of years ago, maybe, but I couldn't find it to look back on advice. I did follow one piece of advice at that time and removed the crumbling foam from the front part of the seat and layered up the thin camping foam that you would lay a sleeping bag on. It is more solid than the original foam and maybe I should just bite the bullet and fork out for a new foam from Leighton's (£100, approx). How do Leighton seats compare with the originals for comfort?

Motorcycling is not the only thing I do that could hurt my back as I do gardening and always end up lifting something I shouldn't. I do do the bent legs bit but sometimes I am stuck in some awkward position where I can't get a proper hold. Digging while bent under some tree is not good, either.

My back is normally passable but get flare ups occasionally, usually the next day, rather than at the time of the deed.

Dave
1 member likes this
#823828 Sep 15th a 04:47 AM
by Mark Z
Mark Z
Originally Posted by Gordon Gray
Originally Posted by Mark Z
<snip>As suggested above, make sure yours are on the lowest spring pre-load setting.

Mark, if his shocks are bottoming out going over potholes then he needs to stiffen up the action....right? It’s as much of a question as a reply.

Gordon

As surmised, changing the spring pre-load does not change the spring rate. IOW, the amount of force it takes to bottom the spring does not change. If the spring is bottoming on bumps, the only solution is stronger springs.
1 member likes this
#823923 Sep 15th a 08:53 PM
by Mark Z
Mark Z
It is a bit subtle; I had to learn about this when we added rear suspension to our electric mobility scooters.

For a simple spring (not progressive), the rate is a fixed number of lbs. per inch. So if it takes X lbs. to compress one inch, it takes 2X pounds to compress two inches, and so on. If the total range of movement is, say, three inches, then 3X lbs. will fully compress the spring, regardless of the pre-load setting.

Pre-load DOES affect "the ride", however, insofar as less pre-load will allow more movement with less force. As in the example above, NO pre-load will allow the spring to compress 1 inch with X lbs. of force. If the spring is already compressed an inch, then it will take 2X lbs. of force to compress it any further, which makes the ride feel "harder".

So with a simple spring, you're confined to a certain minimum and maximum load and range of movement. A progressive spring is called that because the rate is progressive; that is, the amount of force required to compress the spring increases at a greater rate the more it's compressed. This allows a wider range between the minimum and maximum load requirement. (Sorry, I'm probably stating the obvious at this point.)

By the way, we're using two motorcycle-type spring-over shocks on our mobility scooters, and production cost mandates simple springs. So we had to engineer for the heaviest typical load, and sacrifice comfort for very light riders. The problem is somewhat mitigated by the fact that the batteries in these vehicles (2 Group 31 marine deep cycle batteries) together weigh 125 lbs.
1 member likes this
#823966 Sep 16th a 07:38 AM
by dave jones
dave jones
That was a good explanation from Mark. I never really understood about shocks. I had a look at some progressive shocks and they are quite expensive.

Dave
1 member likes this
#824148 Sep 18th a 03:16 PM
by Mark Z
Mark Z
Originally Posted by Allan G
It allowed my legs to be more under my bum, so when I hit a bump my legs take some of the impact and if anything allow me to lift some of my weight off the seat, when your legs are forward it’s much harder to do this without pulling on the bars for assistance.

It also helps if your spine is not vertical when you hit bumps. I wish I had figured this out years ago.
1 member likes this
#824278 Sep 20th a 02:31 PM
by Mark Z
Mark Z
Originally Posted by dave jones
I do seem to sit bolt upright on my bike. It is a normally set up American export 1967 TR6R with standard wide bars. The Uk bars would get me leaning forward a bit, maybe.

I have late-sixties Triumph bars on my A65, with a 5-inch rise. I reduced the length from 32 inches to 29 by cutting an inch and a half off either end. I guess I normally ride pretty straight-up, but when I'm encountering bumps, I scoot my butt back on the seat and lean forward.

I tried the "home market" BSA bars and didn't like them; they gave me a stiff neck from holding my head up. Also, they offered no leverage on rough terrain.
1 member likes this
Job CycleBritish Cycle SupplyMorries PlaceKlempf British PartsPodtronicVintage MagazineBSA Unit SinglesBritBike SponsorBritish Tools & FastenersBritBike SponsorBritBike Sponsor






© 1996-2021 britbike.com
Powered by UBB.threads™ PHP Forum Software 7.7.5