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Top Speed and alloys

Posted: Wed Dec 01, 2004 11:15 am
by dubmk4
recently got a new set of alloys 6.5x15 (195/45/15) steering feels lighter more grip good stuff. top speed seems to be lower though. Car is 1L mpi model 97 standard engine apart from induction kit. Used to be alble to stretch it well over 95mph and got a ton out of it once. now it wont go over 90mph.Any answers. I know bigger wheels are supposed to put speedo readings out but i thought 45 profile tyres were as close to perfect on a mk4 polo to the standard steelies. Or am i wrong :?:

Re: Top Speed and alloys

Posted: Wed Dec 01, 2004 11:56 am
by bstardchild
dubmk4 wrote:recently got a new set of alloys 6.5x15 (195/45/15) steering feels lighter more grip good stuff. top speed seems to be lower though. Car is 1L mpi model 97 standard engine apart from induction kit. Used to be alble to stretch it well over 95mph and got a ton out of it once. now it wont go over 90mph.Any answers. I know bigger wheels are supposed to put speedo readings out but i thought 45 profile tyres were as close to perfect on a mk4 polo to the standard steelies. Or am i wrong :?:
195/45/15 are as good a match as you could wish for so your speedo should be same as before

Rolling resistance may play a part on a 1.0 - it certainly has played a part in an increase in fuel usage on my car (MKIV 1.4 CL with 195/45 15's instead of 175/65 13's)

What tyre pressures are you running cos that could make a big difference?

Posted: Wed Dec 01, 2004 1:45 pm
by david burton
the tyre tread pattern may be really inefficient now as opposed to before..... are they budget compared to a quality make before? shouldn't make any more than 1 or 2 mph tho

Posted: Wed Dec 01, 2004 4:57 pm
by Speedlaw
Wider wheels will even have an effect on overall drag, so losing some top speed is normal. Add the extra drag (from the wind) and rolling resistance together and it's pretty normal.

Posted: Wed Dec 01, 2004 7:21 pm
by carmadaaron
Speedlaw wrote:Wider wheels will even have an effect on overall drag, so losing some top speed is normal. Add the extra drag (from the wind) and rolling resistance together and it's pretty normal.
to add to rolling resistance, if the tyre is under inflated then it will cause more resistance....

i had mine at 2.1bar all round

Posted: Thu Dec 02, 2004 9:42 am
by 13twelve
one of the local mechanics who has a 1.0 polo on 15s told me he got over 100 out of his car

my 1.4's top speed hasnt noticeable changed since putting on 15s

Posted: Thu Dec 02, 2004 3:48 pm
by Musicfreek2002
Ive got a 1.0L MPI and I got 195/50/15's on it and ive managed 107 out of mine which i was impressed at. but now i got the wheels on there it struggles to get to 100.

Posted: Thu Dec 02, 2004 9:57 pm
by Nelson
I'm sorry but how the hell did you get 107 out of a 1 litre polo??

Posted: Thu Dec 02, 2004 10:50 pm
by carmadaaron
yea 107 sounds a bit high for a 1.0.. unless it was downhill

the 1.4 CL with 60bhp does 100mph

Posted: Fri Dec 03, 2004 12:09 am
by bstardchild
carmadaaron wrote:yea 107 sounds a bit high for a 1.0.. unless it was downhill

the 1.4 CL with 60bhp does 100mph
Hmmm either my speedo or the revcounter must be well out then :roll:

speed

Posted: Fri Dec 03, 2004 10:07 am
by jon_poloV
all on a private road officer! :lol:

Posted: Fri Dec 03, 2004 4:49 pm
by dubmk4
i've got yokohama tyres on it cant remember type or pressure about £40 each. wheels are 6.5 x15 so suppose that is abit of a jump in width compared to steelies. old tyres were uniroyal on the back an ats cheap job on front left because of a puncture and something crap on the front right.
Fuel consumption seems the same. I'll just have to put up with a lower top speed :( although its accelerating faster through 2nd 3rd and 4th which is good :)

Posted: Fri Dec 03, 2004 6:21 pm
by Musicfreek2002
I cant really prove it to you but thats your choice i suppose. By the way my engine is standard aswell. I need to calm my driving down now as ive only had the car 10 months and im on my 2nd wheel bearing replacment

Posted: Fri Dec 03, 2004 6:32 pm
by polopowah
1.0 on 16's 195,45,16 use to get 100+ tops now it struggles to get over 90 :cry:
and fuel consumption is terrible, would that have anything to do with the induction kit and backbox fitted? losing back-pressure?
-Ben-

Posted: Fri Dec 03, 2004 10:51 pm
by dubmk4
Musicfreek2002 wrote:I cant really prove it to you but thats your choice i suppose. By the way my engine is standard aswell. I need to calm my driving down now as ive only had the car 10 months and im on my 2nd wheel bearing replacment
were you going downhill when doing that speed? as 104mph was tops on mine on slight down hill section of motorway, with little fuel in the car as well. was prob the max i'll ever get out of it with the engine standard.