...but if it's fixed then that's good news, probably
After my IVA fail, I've got the mechanical bits scheduled for the next couple of weekends. But I wanted to make a swift start on one issue, which
is the design weights. I put 361Kg for axle 1 and 409Kg for axle 2, for a combined gross weight of 770Kg. They calculated it at 331Kg axle 1 and 430Kg
axle 2, 762Kg combined. To be honest I'm impressed how close I was, but obviously having my design weight lower than actual is the kicker
here.
How do I change the design weights? One thing I was looking at said put the new weights on the manufacturer plate, does that override the values on
the application form? I did the form electronically so I am expecting to have to make the change either by email or by snail mail.
I've sent an email to approvals@dvsa.gov.uk who were looking after my initial application, is that a reasonable place to start?
Well, I started this morning with an email in my inbox saying that they've made the changes. There was me thinking it was going to be an uphill battle with all sorts of evidence and letters to submit, and instead it was 'yep, all done, fix the other defects and submit it for a retest'.
Hmm DVSA being helpful, it sounds like a trap to me
...but if it's fixed then that's good news, probably
quote:
Originally posted by JAG
Hmm DVSA being helpful, it sounds like a trap to me
...but if it's fixed then that's good news, probably
that is good,
I thought most people put weights as 450/450/900 to give flexibility.
weights are used for tyre suitability, braking performance,
and I can't think of anything else
quote:
I have the email though so I'll print it and take it with me
What have you changed it too? In your other message you mentioned weights in the low 400's (Kg), the design weight (Max DGW) is the total weight
of car full of fuel luggage & passengers & should then have a bit more added to give "headroom", but you don't want to go too
high or it will fail on brake test!
I would get advice from the actual manufacturer HTH
quote:
Originally posted by russbost
What have you changed it too? In your other message you mentioned weights in the low 400's (Kg), the design weight (Max DGW) is the total weight of car full of fuel luggage & passengers & should then have a bit more added to give "headroom", but you don't want to go too high or it will fail on brake test!
I would get advice from the actual manufacturer HTH
quote:
Originally posted by Slimy38
I've put it as 400Kg for the front and 500Kg for the rear. That's what the examiner suggested,
OK, I think I've made another cock up on numbers...
My braking effort with the current DGW of 770Kg is 66.88% and a pass. If I understand that percentage, it means I have a braking force of 515Kg.
I've changed the design weights to 400/500, for a total of 900Kg. If I work out the braking efficiency, assuming the same braking force of 515Kg,
I end up with an efficiency of 57%. That's lower than the 60% threshold.
However the form also includes the fact that both front wheels locked, so in theory the braking effort is then more about tyre traction rather than
actual braking effort.
The IVA says 'The service brake performance must be at least 60%, (of the CLW or DGW as determined to be the highest) or more than half the
road wheels lock.'.
Do I need to reduce the design weight to get to 60%, or will the wheels locking be the deciding factor here?
If you achieve lockup on an axle you've effectively reached max brake force on that axle, the limit being made by tyre adhesion NOT brake
efficiency, so you don't need to worry about brake efficiency (which I think you said they weren't retesting anyway?)
Good luck with the retest
quote:
Originally posted by russbost
If you achieve lockup on an axle you've effectively reached max brake force on that axle, the limit being made by tyre adhesion NOT brake efficiency, so you don't need to worry about brake efficiency (which I think you said they weren't retesting anyway?)
Good luck with the retest
And yeah he did say he wouldn't repeat the brake testing.
quote:
Originally posted by russbost
If you achieve lockup on an axle you've effectively reached max brake force on that axle, the limit being made by tyre adhesion NOT brake efficiency, so you don't need to worry about brake efficiency (which I think you said they weren't retesting anyway?)
Good luck with the retest