Different diameter rear tires

mxtdiguy · Oct 21, 2017

Is there any reason I cannot install larger rear tires ? Will the computer freak out?
I didn't check the size of the spare tire, I assume it is smaller in which case there must be some allowance for different rotational speeds between wheels
?
Thanks!

manyVAGs · Oct 21, 2017

You may have to live with a TPMS light which will not turn off

Darth_Furious · Oct 21, 2017

I went up to a 55 tire instead of a 45 on my rear on my 2010 jsw. I don't recommend it. The headlights aimed a little lower but I corrected it. The rear seemed to stress the suspension a little more. I started getting squeaks and I broke my upgraded rear sway bar (which is supposed to be strong).

The 2015 gsw has a different tpms and torsion beam, but I learned my lesson and will not repeat on this car

Mike in Anchorage · Oct 22, 2017

If anything, I would also expect the antilock braking system to cause you some problems. Most of them depend on the same rotational rate to determine which wheel needs more or less brake pressure applied. Why not just go bigger tires on all 4? So what if your speedo is off a bit?

740GLE · Oct 23, 2017

why just the rears?

up the fronts as well, you should be fine. Stock Alltrack is 205-55-17, half the lift of the alltrack over the GSW is the taller tires.

I plan to score 205-65-16 for winter tires, reports of 215-60-16 fitting without rub.

mxtdiguy · Oct 23, 2017

I'm hesitant to go much bigger in the front because there seems to less room and larger tires would also take away some torque, although not much. I think I will install 1.5" taller ones in the rear and maybe 1" taller up front.

I did find some 15" rims on tirerack, but I'm going to check the local VW dealer as well

Good point on the braking system, although don't most systems allow for temporary spare tires?

So far ground clearance hasn't been an issue, but we have large nasty speed bumps here and a lot of them are almost complete invisible ! ( no paint, hidden in the shade of a tree )

I do like to explore light off road trails and having already cracked the pan on my 01 Jetta once, the higher the better for me.

mxtdiguy · Oct 23, 2017

Based on the fact that 215/60/16's fit up front, I'm thinking 215/65/15's (1" taller) up front and maybe 235/70/15's (3" taller ) in the back.

This will give 1/2" lift up front and 1.5" lift in the back

Might have to shim up the rear springs to prevent rubbing, or find taller springs

Anyone have a loose oem rear tdi sportwagen spring ?

Darth_Furious · Oct 23, 2017

when you accelerate, the wheels turn forward, but as long as there is grip on the road, there is a counter force pushing the car toward the trunk. You see it clearly in muscle cars (think Vin Diesel in Fast & Furious) where the front 2 wheels lift off the ground. Since VW golfs are front wheel drive, the counter force will never lift the front wheels up. Instead, the front stays planted on the ground and the trunk sinks down a little.

I can see this clearly when I drive at night and from a stop light, my headlights angle up a little when I accelerate from a red light and then drop back down. It's probably 5-10 degrees but very noticeable when you look for it. If the rear wheels are taller and the springs/struts are not corrected, the weight balance will put additional stress on the rear struts/springs each time you accelerate. It will most likely lead to premature wear. I snapped a 25mm upgraded sway bar from the extra stress when I went taller on the rears.

I recommend getting taller tire on all 4 wheels

1854sailor · Oct 23, 2017

mxtdiguy said:
Is there any reason I cannot install larger rear tires?...

One question: Why not just install lift springs?

Darth_Furious · Oct 23, 2017

1854sailor said:
One question: Why?

He said in his posts he wants more ground clearance. I think taller springs and struts may do it. I read of people taking Tiguan parts and putting them on the MK6 JSWs to get more clearance. The GSW might be able to do that too. Or maybe golf alltrack parts

mxtdiguy said:
Based on the fact that 215/60/16's fit up front, I'm thinking 215/65/15's (1" taller) up front and maybe 235/70/15's (3" taller ) in the back. This will give 1/2" lift up front and 1.5" lift in the back
....
So far ground clearance hasn't been an issue, but we have large nasty speed bumps here and a lot of them are almost complete invisible ! ( no paint, hidden in the shade of a tree )

I do like to explore light off road trails and having already cracked the pan on my 01 Jetta once, the higher the better for me.

1854sailor · Oct 23, 2017

Darth_Furious said:
He said in his posts he wants more ground clearance...

Saw that after I posted. See edit. MK VII platform is different from the Jetta Sportwagen. I doubt the lift springs are the same, but there are probably some out there that will fit. Definitely a better option than taller tires.

mxtdiguy · Oct 23, 2017

Taller springs are something I'm going to pursue. If I can get the dimensions of the stock spring I think I will be able to find a spring from Moog to fit:

http://www.moog-suspension-parts.com/universal_coil_springs.asp

In order to estimate the rate of the stock spring I will first have to weigh the rear of the car, then measure how much they deflect from full extension to ride height.

Springs themselves are not high tech, just finding the stock parameters and selecting an alternate spring is the trick.

I've read that Tiguan springs can be used but are stiffer and provide 1/2 of lift.
I would prefer a stock rate or slightly softer and about 1" of lift.

mxtdiguy · Oct 23, 2017

Darth_Furious said:
when you accelerate, the wheels turn forward, but as long as there is grip on the road, there is a counter force pushing the car toward the trunk. You see it clearly in muscle cars (think Vin Diesel in Fast & Furious) where the front 2 wheels lift off the ground. Since VW golfs are front wheel drive, the counter force will never lift the front wheels up. Instead, the front stays planted on the ground and the trunk sinks down a little.
I can see this clearly when I drive at night and from a stop light, my headlights angle up a little when I accelerate from a red light and then drop back down. It's probably 5-10 degrees but very noticeable when you look for it. If the rear wheels are taller and the springs/struts are not corrected, the weight balance will put additional stress on the rear struts/springs each time you accelerate. It will most likely lead to premature wear. I snapped a 25mm upgraded sway bar from the extra stress when I went taller on the rears.
I recommend getting taller tire on all 4 wheels

I took a look under the rear of the car again without lifting it and didn't see a sway bar on my 2016 DSW tdi....

Darth_Furious · Oct 23, 2017

The jsw has a sway bar. The golf sportwagen has a torsion beam. It won't snap. Instead, the next weakest part may break. That is what prevents me from changing the dynamic by getting oversized rear tires

turbobrick240 · Oct 23, 2017

The ABS isn't going to like a hodgepodge of tire sizes. Not good for tire rotations either. I have some pretty well worn tires on the back of my golf and nearly new tires of the same size on the front. That relatively small diameter difference is enough to make my ABS/traction control unhappy.

740GLE · Oct 24, 2017

turbobrick240 said:
The ABS isn't going to like a hodgepodge of tire sizes. Not good for tire rotations either. I have some pretty well worn tires on the back of my golf and nearly new tires of the same size on the front. That relatively small diameter difference is enough to make my ABS/traction control unhappy.

not telling whats what, but the new tires should always be installed on the rear axle and the partially worn tires moved to the front. New tires on the rear axle help the driver more easily maintain control on wet roads since deeper treaded tires are better at resisting hydroplaning.

jerrymander · Oct 24, 2017

Darth_Furious said:
I went up to a 55 tire instead of a 45 on my rear on my 2010 jsw. I don't recommend it. The headlights aimed a little lower but I corrected it. The rear seemed to stress the suspension a little more. I started getting squeaks and I broke my upgraded rear sway bar (which is supposed to be strong).

what

how is that even possible

turbobrick240 · Oct 24, 2017

740GLE said:
not telling whats what, but the new tires should always be installed on the rear axle and the partially worn tires moved to the front. New tires on the rear axle help the driver more easily maintain control on wet roads since deeper treaded tires are better at resisting hydroplaning.

Huh, never heard that one before. Haven't really run into any hydroplaning problems. I tend to slow down in inclement weather. I'm just being a cheapskate while maintaining decent fwd traction. I plan to replace the worn rear tires with snows in a month or two and put them on the front.

740GLE · Oct 25, 2017

Just from what I've read, obviously you won't flip off the road because of it. I grabbed that quote from tirerack.

I think the fear is if you slam on the brakes while not going 100% straight, with the weight is shifting forward the back end is more likely to come around if you have bald tires back there, you need as much grip as you can.

Darth_Furious · Oct 25, 2017

jerrymander said:
what

how is that even possible

I had a 25mm neuspeed sway bar. I took a right turn kinda hard onto a parking lot and heard a loud thunk. I took it to a shop and they showed me the sway bar snapped. I couldn't believe it either.

Darth_Furious · Oct 25, 2017

turbobrick240 said:
Huh, never heard that one before. Haven't really run into any hydroplaning problems.

I seen videos of fwd and rwd cars fishtailing when the back tire is bald in wet conditions on a slight turn. The safety video showed a side by side video of the same car with the tires rotated. It still slipped around a little but was much better. The recommendation is good tires on the back regardless of the drive wheels if you anticipate rain

turbobrick240 · Oct 25, 2017

Darth_Furious said:
I seen videos of fwd and rwd cars fishtailing when the back tire is bald in wet conditions on a slight turn. The safety video showed a side by side video of the same car with the tires rotated. It still slipped around a little but was much better. The recommendation is good tires on the back regardless of the drive wheels if you anticipate rain

Yeah, in a perfect world we'd all have brand new tires on all four corners all the time. I know from experience that better traction from the drive wheels can be helpful at times. Whatever the safety police say. I certainly wouldn't put a pair of tire chains on the back of a fwd car rather than the front.

mxtdiguy · Nov 7, 2017

1854sailor said:
One question: Why not just install lift springs?

Yes, lifting it with taller springs is something I will be doing (alltrack springs plus spacers ), but I learned that the MK7 golfs measure tire rotation instead of getting readings from a sensor in the wheel, so I will be install same tires front and back.

But, unless a tire "balloons" from being inflated, the revolutions per mile don't change when deflation a tire since the circumference stays the same...so the VW way of measuring pressure must be ultra sensitive!

740GLE · Nov 8, 2017

turbobrick240 said:
Yeah, in a perfect world we'd all have brand new tires on all four corners all the time. I know from experience that better traction from the drive wheels can be helpful at times. Whatever the safety police say. I certainly wouldn't put a pair of tire chains on the back of a fwd car rather than the front.

And I know from experience the times you need traction is in corners and emergency breaking, not off the line speed, with how much these cars understeer the last thing you need is the back end steeping out. if you under steer you're going to fast for the road conditions and can correct it by slowing down, if you oversteer in a FWD car you're along for the ride.

Don't think anyone said anything about chains, the statement isn't just about winter driving its for year round driving.

As for what tires to roll on, 4 used tires in uncle henrys are dirt cheap, I'd much rather grab a used set than buy just two new and run questionable ones on the front, but to each his own.

740GLE · Nov 8, 2017

Darth_Furious said:
I had a 25mm neuspeed sway bar. I took a right turn kinda hard onto a parking lot and heard a loud thunk. I took it to a shop and they showed me the sway bar snapped. I couldn't believe it either.

Just think of all the weight savings you gained by buying a hollow bar!

Darth_Furious · Nov 8, 2017

740GLE said:
Just think of all the weight savings you gained by buying a hollow bar!

the oem one was hollow as well so i'm sure that would have snapped as well. the shop i go to recommended this one so i went with it. maybe next time i go with a solid bar. unfortunately the mk7 has a torsion beam so i can't get one

turbobrick240 · Nov 8, 2017

740GLE said:
And I know from experience the times you need traction is in corners and emergency breaking, not off the line speed, with how much these cars understeer the last thing you need is the back end steeping out. if you under steer you're going to fast for the road conditions and can correct it by slowing down, if you oversteer in a FWD car you're along for the ride.
Don't think anyone said anything about chains, the statement isn't just about winter driving its for year round driving.
As for what tires to roll on, 4 used tires in uncle henrys are dirt cheap, I'd much rather grab a used set than buy just two new and run questionable ones on the front, but to each his own.

The typical American driver isn't all that skilled at handling emergency maneuvers. And for an unskilled driver, understeer is far easier to deal with than oversteer. So for the general populace, putting the better tire tread in the rear tires of fwd cars is probably solid safety advice. If you were to ask a skilled fwd rally car driver like Erik Carlsson where he'd rather have the good tires, it wouldn't be in back.

Ol'Rattler · Nov 8, 2017

Been there, done that. It was a a 90 degree off camber freeway exit that I usually took fairly fast. Worked great with the pavement dry. One time when the pavement was wet, I took it at my usual speed.

Well, the suspension unloaded slightly because the road surface was somewhat irregular and I lost traction and went into a slide. I came off of the gas, tried to correct and the car went from a slight understeer to a full on spin like a hockey puck oversteer.

Talk about being along for the ride. By some miracle I ended up facing the wrong way about 6 inches from the guard rail. Other than driving to fast conditions. What could have been Darwin's final reward for me was letting off of the gas. Instant MAX oversteer.................

A very enlightening read: http://forums.tdiclub.com/showthread.php?t=133342

Different diameter rear tires

Veteran Member

Well-known member

Veteran Member

Veteran Member

Top Post Dawg

Veteran Member

Veteran Member

Veteran Member

Resident Curmudgeon

Veteran Member

Resident Curmudgeon

Veteran Member

Veteran Member

Veteran Member

Top Post Dawg

Top Post Dawg

Veteran Member

Top Post Dawg

Top Post Dawg

Veteran Member

Veteran Member

Top Post Dawg

Veteran Member

Top Post Dawg

Top Post Dawg

Veteran Member

Top Post Dawg

Top Post Dawg