Bottoming out front end - what to change?

[jay987]

hi all
was testing in pembrey on saturday and was runinng 1.14 a lap, but the problem was that the front end was bottoming out, i have 10w oil and runing progress springs, i a bit stuck in what to change and need a bit of advice of what to fit and what everyone is running or just advice.

cheers all

[jimmyb]

I was running 20w in mine with ktech springs at 9.5 and I weight about 15stone in leathers. Iv got cartridge conversion that me and a friend did over winter so just waiting for first trackday now :-)

[jay987]

thanks jimmyb
how do i know what size springs i would need?

[Berlin]

You sure you're bottoming out progressive springs?

The whole idea of progressive springs is that they increase in rate when they're compressed so to bottom them out you'd have had to go past the highest rate of the progression and I'd imagine thats higher than the "right" springs for you.

What do you weigh?

C

[yorkie_chris]

If you are bottoming a lot you need more oil in there or stiffer springs.

[jay987]

i weigh about 10 stone with out my gear on

[Berlin]

Took me a while to find this cos some **** changed the title again!

Anyway, At 10 stone you shouldn't be bottoming the progressive springs out. What you may be doing is reaching the end of the linear travel and encountering the progressive travel which feels like them bottoming out. I'm twice your weight and I doubt I could bottom them out.

Did you have a marker on the stanchion? was it right up by the yoke if you did? if not, you need to do this to make sure.

For your weight you're looking at linear springs of about .85 or even point .80 (I think I have some of them somewhere) and 15 weight Oil for the track. and you shouldn't be bottoming those out. They are only just up from std.

Do you know how to measure your static (http://www.sportrider.com/tech/146_0308_set_your_static_sag/index.html) and rider sag setings. it would be good to know them.

Cheers, C

[northwind]

What you need, is a cable tie round the fork leg. Really doubt you're bottoming it out like that.