The Spares Company
Club Shop/Regalia
Parent Website
Contact Officials
Machine Registrar
Club Secretary
Membership Secretaries
MPH Editor and Forum Administrator.
Section Newsletters
Technical Databases
Photos
Home
What's new
Latest activity
Forums
New posts
What's new
New posts
Latest activity
Information
Bike Modifications
Machine Data Services
Manufacturers Manuals
Spare Parts Listings
Technical Diagrams
Whitakerpedia (Vincent Wiki)
The Club
MPH Material Archive
Flogger's Corner
Obituaries
VOC Sections
Local Sections
Local Section Newsletters
Miscellaneous
Club Assets
Club History
Club Rules
Machine Data Services
Meeting Documents
Miscellaneous
Essential Reading
Magazine/Newspaper Articles/Letters
Adverts and Sales Brochures
The Mighty Garage Videos
Bikes For Sale (Spares Company)
Log in
Register
What's new
New posts
Menu
Log in
Register
Install the app
Install
Home
Forums
Forums: Public Access
Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
Modified Steering Stem
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="timetraveller" data-source="post: 78166" data-attributes="member: 456"><p>Greg, can I just check that I have understood you correctly. Your combination of a 50 lb/inch spring and a 33 lb/inch spring is equivalent to a pair of 41.5 lb/inch springs. Call that 42lb/inch. I confess that I had never considered what would be happening if one was doing a 'stoppy' when all the weight of both the rider and bike are on the front wheel. In an extreme case that could be 650 lbs and even with a 'seven stone weakling' it would be about 550 lbs. If the springs are exerting a force of 200 lbs with the bike stationary and perhaps 250 lbs with the rider on board they have to exert an additional force of 300 to 400 lbs. This over a movement of about 2". Recalling that there are two springs this leads to a required spring rate of about 75 lbs/inch to about 100 lbs/inch. If the travel allowed is increase to 2.5" then those springs rates decrease to 60 lbs/inch and 80 lbs/inch. Those are pretty serious springs and are not likely to be conducive to comfort. It seems to me therefore that either we have to accept the fact that under really severe braking the forks are going to bottom out, and I assume that under those conditions the last thing on ones mind is comfort, and we can have some comfort or we give up one the comfort and settle for a hard, barely moveable front end. The question is, are you satisfied that with the equivalent of two 42 lbs/inch springs and two inches of pre-load you have the correct compromise between topping out, bottoming out and comfort? There is no problem getting springs like that made but I am already out of pocket on springs and don't want to have to increase the price of the steering heads to try to recover that money. The orders is already in for 30 new steering heads to be machined in the new batch with some with your mod and some to use the Oilite bushes.</p><p></p><p><strong><span style="font-size: 18px">Additionally could I now ask those who want to use Greg's mod and want the lower links to be opened up here to now contact me and then send their lower links. I already have four and it makes sense to machine the whole lot in one batch. Thank you.</span></strong></p></blockquote><p></p>
[QUOTE="timetraveller, post: 78166, member: 456"] Greg, can I just check that I have understood you correctly. Your combination of a 50 lb/inch spring and a 33 lb/inch spring is equivalent to a pair of 41.5 lb/inch springs. Call that 42lb/inch. I confess that I had never considered what would be happening if one was doing a 'stoppy' when all the weight of both the rider and bike are on the front wheel. In an extreme case that could be 650 lbs and even with a 'seven stone weakling' it would be about 550 lbs. If the springs are exerting a force of 200 lbs with the bike stationary and perhaps 250 lbs with the rider on board they have to exert an additional force of 300 to 400 lbs. This over a movement of about 2". Recalling that there are two springs this leads to a required spring rate of about 75 lbs/inch to about 100 lbs/inch. If the travel allowed is increase to 2.5" then those springs rates decrease to 60 lbs/inch and 80 lbs/inch. Those are pretty serious springs and are not likely to be conducive to comfort. It seems to me therefore that either we have to accept the fact that under really severe braking the forks are going to bottom out, and I assume that under those conditions the last thing on ones mind is comfort, and we can have some comfort or we give up one the comfort and settle for a hard, barely moveable front end. The question is, are you satisfied that with the equivalent of two 42 lbs/inch springs and two inches of pre-load you have the correct compromise between topping out, bottoming out and comfort? There is no problem getting springs like that made but I am already out of pocket on springs and don't want to have to increase the price of the steering heads to try to recover that money. The orders is already in for 30 new steering heads to be machined in the new batch with some with your mod and some to use the Oilite bushes. [B][SIZE=5]Additionally could I now ask those who want to use Greg's mod and want the lower links to be opened up here to now contact me and then send their lower links. I already have four and it makes sense to machine the whole lot in one batch. Thank you.[/SIZE][/B] [/QUOTE]
Insert quotes…
Verification
What was Mr Vincent's Christian Name?
Post reply
Home
Forums
Forums: Public Access
Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
Modified Steering Stem
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
Accept
Learn more…
Top