Wheel sizes and top end speed

Post by **slobbo** » 26 Oct 2006, 18:48

I've just bought Russels (Syncro Nutz) Syncro and am planning on getting a set of wheels and All terrains for it. I have discovered that the beast struggles on the hills at motorway speeds (no probs off road) so I wanted to find out what I can expect from a tyre size change.

Anyone know of any websites that work this stuff out for you?

Post by **Hacksawbob** » 26 Oct 2006, 21:06

bigger tyres = bigger gears so more top end gearing. I think!

Post by **KarlT** » 26 Oct 2006, 21:31

Yeah but you will notice a drop in acceleration

Post by **HarryMann** » 27 Oct 2006, 00:55

Its all here, including a TRC calculator

http://www.club80-90syncro.co.uk/Syncro ... _trans.htm

Post by **toomanytoys** » 27 Oct 2006, 08:14

Mmm...
Motoryway speeds... ?? what 70 or more?

I would have though Russel will have set that up pretty well

What vehicles are you used to driving? the T25 isnt so much like a "modern" vehicle..
Bigger diameter tyres will not help the "stuggle" unless its running out of revs... RPM = mph???

Post by **HarryMann** » 27 Oct 2006, 09:36

Sounds more like its overgeared than undergeared, if it struggles a bit on long motorway hills. Was there a headwind or sidewind at the time as well.

Or expect to back off a bit and come down a gear under those circumstances, else by reducing TRC you'll lose motorway cruising ability.

Post by **toomanytoys** » 27 Oct 2006, 09:39

Yes, sounds like its overgeared, but it has more grunt etc (TDi isnt it?) and isnt a overweight hightop etc....

Post by **HarryMann** » 27 Oct 2006, 09:47

TD I think... gearde and tyred for cruising. Mine was a bit gutless on MWay hills till I overboosted and overfuelled it and this will be heavier than mone (though vould scarcely be draggier

).

Like someone said, what sort of vehicles are you used to? Heavy trucks and vans tend to have to accept a reduction in cruising speed when up against long hills or headwinds.

Post by **bigbluebus** » 27 Oct 2006, 11:41

mines a bit gutless on long hills too. I tend to sit around 60 - 65 ish, but if I then nail it it feels 'flat'

But . . sit it around 70, go for more gas (i.e bottom of a long hill) and it picks up nicely

I know my engines sweet now and everythings working as it should

I'm well aware my interiors on the heavy side but it had crossed my mind it's got 14" diffs with 16" wheels

Really should invest in a rev counter . .

Post by **Trundler** » 27 Oct 2006, 11:44

I think it's all a matter of making that mental adjustment. Once you have you can chill out and arrive at journey's end much fresher

I'm quite pleased that my cruising speed has remained the same, even after changing from a 1.9 up to a much faster 2.1. I'm really living up to the Trundler tag now.....

Slows down on hills? Yeah. ... so...?

Post by **bigbluebus** » 27 Oct 2006, 11:48

I don't mind the drop off in speed as such, if anything it amuses the crap out of me watching people getting annoyed

I just find it unpleasant on the motorway when I check my mirrors to see 40 tonnes of half asleep Polish death truck bearing down on me

Post by **toomanytoys** » 27 Oct 2006, 11:55

Biggest issue I have is..
Although my 1.9 runs real well and sits at 3800-4000 rpm all day ( and does have too) the speedo is reading too high, (10kmh).. if I was actually doing 110kmh I wouldnt mind so much... Gonna go for some 205/14 that should pull it up... but my off road tyres are 205/70 15, but are actually bigger than 215/75 15 BFG's....

so gear it up a bit much for the puny 1.9 DG.....

You comming out to play Saterday Andy?? good to meet up again...

Post by **syncropaddy** » 28 Oct 2006, 08:50

Hi ... Russells red van runs 235/75/15 MT and these are way bigger than normal and will have a few probs on long hills as there isnt the torque to allow smooth passage. Try 225/70/15 Long Trails on 7 x 15 rims. That will make a difference

Post by **HarryMann** » 28 Oct 2006, 08:53

There ya go, sounds like the first port of call to me... the tyre shop

Post by **Russel** » 28 Oct 2006, 19:12

Slobo was advized this if doing a lot of motor way driving since this
vehicle was setup by myself more for offroading than motorway use.
The only difference is i advized him to use 215 80 15's on a Generall grabber tred.