Snow tire - size matters? | GTAMotorcycle.com

Snow tire - size matters?

justride

Well-known member
I have 18's on my CRV right now. Was wondering if it's ok to get 17 inch rims and 17 inch snow tires. Anything to consider if I size down for the winter. Trying to save some cash if I can. thanks
 
both hubby and I downsized our winter tires...me by 1" (16 down to 15) and hubby 3" (20 down to 17)...his especially were a lot cheaper...never had a problem with mine and I've had them since 2013...
 
I have 18's on my CRV right now. Was wondering if it's ok to get 17 inch rims and 17 inch snow tires. Anything to consider if I size down for the winter. Trying to save some cash if I can. thanks
I have 18" stock on my Mitsubishi Eclipse GT-P and 16" snows. It sits a bit low, but it's not going to affect anything. You speedo will be off by a few kph. If you're going from 18 to 17 and chose the correct sidewall, your speedo will be unaffected as you've not changed the circumference.

Get some Fluid Film and spray your steel rims (while they're off the car only) and they'll last a lot longer.
 
what you don't want to change is the overall circumference
there are tire/wheel options to go from 18 to 17 while maintaining circumference
and snows tend be a narrower than all seasons

I'd guess that Jayv has given you the right answer
 
Make sure it fits over your brakes, keep the outside diameter the same or at least close and have at er. I run 15" snows, the car comes stock with 16 to 19" rims.

The wifes old car had the same bolt pattern and OD as her new car, but the old rims didnt clear the brakes so we had to get her new snows.

There is a reasonable argument about running narrower snows to better cut through the crap. I run a bit narrower, but I dont know the optimum width.

Smaller rims dull inputs a bit giving you less chance to annoy the contact patch. They also normally save you a fortune in rubber.
 
I did it on a Honda Civic Si worked fine
but had to make sure the front wheel weights don't get knocked of by the calliper, it was that close. ymmv.

just run a taller tyre profile to compensate for the wheel size difference and it works great.
 
As GreyGhost touched on, there's more than just the rim and tire size. The centre bore and offset also need to match your vehicle. And the bolt pattern, of course

A lot of people just blindly buying used snow tires off Kijiji find out the hard way that the "same size" tires don't even fit their car, much less smaller ones.

As for actually going smaller when you sort out the correct rim, narrower is actually better for snow tires, so yes, going down a size if possible will certainly help.
 
As GreyGhost touched on, there's more than just the rim and tire size. The centre bore and offset also need to match your vehicle. And the bolt pattern, of course

A lot of people just blindly buying used snow tires off Kijiji find out the hard way that the "same size" tires don't even fit their car, much less smaller ones.

As for actually going smaller when you sort out the correct rim, narrower is actually better for snow tires, so yes, going down a size if possible will certainly help.
You can get away with using wheels with a larger center bore. Offset has little effect.

Best thing to do is go down one size in wheel diameter or two sizes if you can get away with caliper clearance etc and down one size in section width, while keeping overall tire diameter within a couple %
 
Centre bore is very important. If it’s too big the studs carry the load instead of the hub. Studs are not designed to carry loads on cars - they simply hold the tire on. Hubs carry the load. At worst the rims shift on the studs at speed and you get a vibration. At worst the wheel eventually busts the studs and you become one of those people on the side of the road that lost a tire. Hopefully it doesn’t kill someone wherever it flew off to....

Too small, and the rim just won’t fit.

And offset is the difference between wheels fitting over brake calipers, or not, and wheels rubbing inner fenders, or not.

So, respectfully, both are very important
 
Lug nuts provide clamping force via the studs. The inner surface of the wheel clamped to the brake rotor/drum, clamped to the wheel hub, bears load. The centre bore does not bear load, it is only for locating the wheel
 
Do some reading on the topic.

The only exception are rims specifically designed for stud centric loads. And even then the studs may not handle the loads unless the car was designed for stud centric vs bore centric. Bigger studs and appropriate nuts are required.

Ask yourself why bore size adapters for aftermarket rims are a thing.
 
Lug nuts provide clamping force via the studs. The inner surface of the wheel clamped to the brake rotor/drum, clamped to the wheel hub, bears load. The centre bore does not bear load, it is only for locating the wheel
Bingo
Its also the reason aftermarket wheels fit tons of different vehicles despite having different center bores. You can guarantee the wheel is located center using hub ring adaptors or using lugcentric lugs etc.
The clamping force of properly torque lugs is massive.
The heavier the vehicle the more lugs are used typically = higher clamping force.
 
From online:

"The center section of the hub does not support any loading when the lugs are properly and completely torqued. The lugs see clampload in excess of (see below).

The tension in a bolt is given by:

F=T/Kd :: where F==Tensile force; T==torque; K==factor (0.2); d==diameter

So for an M12 torqued to 70ft-lbs:

F=840_in-lbs / .2*(.472_in) = 8898_lbf per lug. At 5 lugs thats 44,491_lbf pulling the wheel in contact with the hub.

Now the loading of the wheel is transfered to the hub on the frictional interface btw the wheel and hub. The following is how to solve for the force required to break that static friction.

f=u(s)*N:: where: f==frictional force required to break static friction; u(s)==Static coefficient of friction; N==normal force (or clamping force)

f=0.45*44,490= 20,000_lbf

So in order to cause the wheel to move in relation to the hub would require ~20,000_lbs of force to act on the wheel independantly of the hub. "

70lbs is undertorqued... usually at least for Hondas its 80ftlbs, so figure about 50000 lbs of clamping force on your typical 5 lug vehicle
 
Do some reading on the topic.

The only exception are rims specifically designed for stud centric loads. And even then the studs may not handle the loads unless the car was designed for stud centric vs bore centric. Bigger studs and appropriate nuts are required.

Ask yourself why bore size adapters for aftermarket rims are a thing.
They are a thing because people would have to be very careful when installing the rim ensure it's centered. Those studs support the car through vertical shearing force, which is way beyond the car weight. Those little $2 plastic rings can't support the whole car now can they?

Sent from my Pixel 3a using Tapatalk
 
I have always gone down one inch wheel (rim) size for winters (I've had Toyota's, Honda's, and VW's). But compensated a little with higher rubber (sidewalls) to maintain overall wheel size. If you car had other models, trim, packages etc with smaller wheel size you should be fine and clear brakes etc. Yes narrower is better for snow. You might be able to save a bit more with a less speed rated tire. You don't always need to go 240 kph in the snow :rolleyes:
 
This is a good calculator for checking if the wheel/tire size you are considering will fit:


You still need to know what your caliper clearance is though. Rule of thumb I've always used is downsize to the smallest size offered from the factory on the same car as the overall diameter will be approximately the same, assuming your model doesn't have larger brakes.

My 2013 gti came with 225 40 18 and I was able to run a 205 55 16, but not the 15 offered on the base golf of the same year because the brakes are bigger. My 2019 gti with the same stock size has even larger front brakes and can only fit certain 17s with enough clearance for the calipers.
 

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