[sard]

Sorry in advance to beat a dead horse and start another thread on snowchains. I just need to prepare for a few snowboarding trips soon and according to the manual and as others have posted, 18's are allowed to have snowchains put on whereas 19's aren't (I have the 19's).

I backed the car up on an 8" ramp under the left rear wheel to try and see clearance issues during compression. I also put a 100 lb weight on the left side of the trunk, 80 lb weight on the left rear passenger foot well, and then had my 130 lb wife stand on the rear left door sill while hanging onto the roof rail.

The narrowest part on the inside of the wheel well (with my attempt at compression) measured 2" in clearance. The "wheel gap" between the top of the tire and the top part of the fender arch is 2"

I'm thinking of getting the Thule XG-12 Pro snow chains which require 12mm of clearance.
http://thule.com/en-US/US/Products/S...le-XG_-_12-Pro

Due to it being near impossible to determine the minimal clearance upon a loaded vehicle upon compression. I have to make guesses. It appears the biggest concern is actually the outside top of the tire crashing into the top of the wheel fender/arch (the surface that has the screws).

According to TireRack's calculator with the following measurements:

19's = 245/45/19 tires on 19x8.5 et 38 wheels (I'm assuming this is the measurement for the rears since my tires are not staggered)
18's = 250/50/18 tires on 18x8 et 43 wheels.

Going from 19" to 18" = 1mm MORE clearance on the strut side, and the outside edge of the wheel will RETRACT 11mm and radius is smaller by 0.0175 inch.

It appears the most significant differences between the 19's and 18's is that the outside edge of the 18's retract by 11mm. All other measurements are insignificant. This is also the area I felt had the greatest risk of crashing together.

What are your thoughts? Completely foolish to ignore the manual and just try it? I think it might still be ok to run the chains on the rears. The fronts are tighter. My only question is with careful driving (and also being limited to low speeds due to having chains on). Will the rear tires ever be compressed enough where the top of the wheel gets within 12mm of the top of the fender arch...With my "compression simulation" I had an additional 2" to go...

Getting another set of snow tires and wheels for it is kinda out of the reach at this point.

Here is a little video of me hitting a jump at Bear Mountain yesterday
http://www.youtube.com/watch?feature...IW7PKgrTA&hd=1

[TogMogX3]

Sard, with snowchains most people forget about the effects of certifugal force. Even at 30MPH or 50KPH the clearance can be critical; have you considered the fabric 'socks'?

[sard]

Originally Posted by TogMogX3

Sard, with snowchains most people forget about the effects of certifugal force. Even at 30MPH or 50KPH the clearance can be critical; have you considered the fabric 'socks'?

I came across a photo of one on the web. Do they work? Do the highway patrol ever not let you by having those when snow chains are required?

[MetaX]

In my experience driving up to Tahoe, I have never seen any AWD/4WD vehicles turned away due to tires or lack of chains. The vast majority of the time chains are only required for 2WD vehicles except under the most extreme of conditions--but by the time conditions warrant this Caltrans is far more likely to simply close the highway off to all traffic than implement R3 controls. While I have been turned back due to highway closures numerous times I have NEVER seen R3 requirements enforced. Unless I were in a snowcat or had those scary looking Mattracks I probably wouldn't want to venture past the checkpoint anyhow. Here's a link to Caltrans' chain control page:

http://www.dot.ca.gov/hq/roadinfo/chcontrl.htm

..And if anyone ever manages to try Mattracks on their X3, PLEASE be sure to share!

http://www.mattracks.com/

[sard]

Originally Posted by MetaX

In my experience driving up to Tahoe, I have never seen any AWD/4WD vehicles turned away due to tires or lack of chains. The vast majority of the time chains are only required for 2WD vehicles except under the most extreme of conditions--but by the time conditions warrant this Caltrans is far more likely to simply close the highway off to all traffic than implement R3 controls. While I have been turned back due to highway closures numerous times I have NEVER seen R3 requirements enforced. Unless I were in a snowcat or had those scary looking Mattracks I probably wouldn't want to venture past the checkpoint anyhow. Here's a link to Caltrans' chain control page:

http://www.dot.ca.gov/hq/roadinfo/chcontrl.htm

..And if anyone ever manages to try Mattracks on their X3, PLEASE be sure to share!

http://www.mattracks.com/

Thanks for the response, I also wanted to be safe though!

[E92LNGCGY]

I don't think snow chains are necessary. A set of proper (good) winter tires are more than enough. You can also add studs which I think is better than snow chains. Those things a a pain in the butt.

[rohan_b79]

[QUOTE=sard;10985371]Sorry in advance to beat a dead horse and start another thread on snowchains. I just need to prepare for a few snowboarding trips soon and according to the manual and as others have posted, 18's are allowed to have snowchains put on whereas 19's aren't (I have the 19's).

I backed the car up on an 8" ramp under the left rear wheel to try and see clearance issues during compression. I also put a 100 lb weight on the left side of the trunk, 80 lb weight on the left rear passenger foot well, and then had my 130 lb wife stand on the rear left door sill while hanging onto the roof rail.

The narrowest part on the inside of the wheel well (with my attempt at compression) measured 2" in clearance. The "wheel gap" between the top of the tire and the top part of the fender arch is 2"

I'm thinking of getting the Thule XG-12 Pro snow chains which require 12mm of clearance.
http://thule.com/en-US/US/Products/S...le-XG_-_12-Pro together.

What are your thoughts? Completely foolish to ignore the manual and just try it? I think it might still be ok to run the chains on the rears. The fronts are tighter. My only question is with careful driving (and also being limited to low speeds due to having chains on). Will the rear tires ever be compressed


Hi sard,
I was thinking of getting Thule k-40 (k-summit series), I don't think they have the usual problem of back side clearance, and need 0-mm clearance. These have been pictured on a Mercedes GLK w/ 19" tires on THULE's catalogue as well.

[torzeck]

I know you've heard this, but chains suck. If they break free, they'll tear up your fender trim and that will end up costing you more than winter tires.

Carry chains with you just to have them for the cops, but get winter tires and you'll get through any weather. Shit, you bought an x3, spend the money.


Also, I'd avoid putting chains on the 19's no matter what.

[sard]

[QUOTE=rohan_b79;10987218]

Originally Posted by sard

Sorry in advance to beat a dead horse and start another thread on snowchains. I just need to prepare for a few snowboarding trips soon and according to the manual and as others have posted, 18's are allowed to have snowchains put on whereas 19's aren't (I have the 19's).

I backed the car up on an 8" ramp under the left rear wheel to try and see clearance issues during compression. I also put a 100 lb weight on the left side of the trunk, 80 lb weight on the left rear passenger foot well, and then had my 130 lb wife stand on the rear left door sill while hanging onto the roof rail.

The narrowest part on the inside of the wheel well (with my attempt at compression) measured 2" in clearance. The "wheel gap" between the top of the tire and the top part of the fender arch is 2"

I'm thinking of getting the Thule XG-12 Pro snow chains which require 12mm of clearance.
http://thule.com/en-US/US/Products/S...le-XG_-_12-Pro together.

What are your thoughts? Completely foolish to ignore the manual and just try it? I think it might still be ok to run the chains on the rears. The fronts are tighter. My only question is with careful driving (and also being limited to low speeds due to having chains on). Will the rear tires ever be compressed


Hi sard,
I was thinking of getting Thule k-40 (k-summit series), I don't think they have the usual problem of back side clearance, and need 0-mm clearance. These have been pictured on a Mercedes GLK w/ 19" tires on THULE's catalogue as well.

I think these will run into the same problem. I believe the "bottleneck" is actually the front where the lateral shoulder of the tire can come into contact with the fender arch with the added width of the device. I have been looking at these also..

[TogMogX3]

[QUOTE=rohan_b79;10987218][QUOTE=sard;10985371]


What are your thoughts? Completely foolish to ignore the manual and just try it? I think it might still be ok to run the chains on the rears. The fronts are tighter. My only question is with careful driving (and also being limited to low speeds due to having chains on). Will the rear tires ever be compressed


If I have read your post correctly, you are considering fitting snow chains on your front wheels - yes?

Trust me this is a complete NO, NO!

[sard]

Togmog: no the rears. Fronts are too tight.

Ok a friend of mine has an X5 M Sport with 20" wheels and aggressive 315/30/20 tires. His manual restricts snow tires also but he has used them without issue on the rears. Here is a photo. I will try the snow chains on rear and test the clearance in dry weather.

[jt2]

Originally Posted by TogMogX3

If I have read your post correctly, you are considering fitting snow chains on your front wheels - yes?

Trust me this is a complete NO, NO!

Ok, I'll bite. Why?

Originally Posted by torzeck

Also, I'd avoid putting chains on the 19's no matter what.

Again, why? I've test-fit SCC low profile cable chains on 19s, and can see now reason not to run them. I've spoken with the service department at the dealer and they agree.

The overall size of 18s and 19s with lower profile tires shouldn't be any different so I'm a bit puzzled by all this.

[TogMogX3]

Originally Posted by jt2

Ok, I'll bite. Why?

jt2, you may have read a post of mine in which I have said that "I do not believe that there is such a thing as a stupid question - only stupid answers". Therefore; please be assured that I do not think that your question is in any way stupid. All that said the reasons why one should NEVER fit snow chains to the front wheels of your X3 are as follow:

BMW do not recommend it. (Please see page 213 of the BMW US PDF User Manual)
As BMW do not recommend fitting snow chains to the front wheels of your X3, in the event of an accident your insurance may be invalid.
In the event that one fits aftermarket wheels complete with none BMW approved tyres complete with snow chains, in the event of an accident your insurance may be invalid.
One shudders to think what could happen in the event that someone is injured or killed as a result of any of the above and one ends up in the Law Courts.

If that said is insufficient reason for you and you still need to be convinced, then I will be pleased to detail the technical reasons too, if asked?

[TogMogX3]

Originally Posted by jt2

Ok, I'll bite. Why?



Again, why? I've test-fit SCC low profile cable chains on 19s, and can see now reason not to run them. I've spoken with the service department at the dealer and they agree.

The overall size of 18s and 19s with lower profile tires shouldn't be any different so I'm a bit puzzled by all this.

Oh! Sorry but I forgot the second question; however, my previous answer is still valid for this too.

[sard]

Originally Posted by jt2

Ok, I'll bite. Why?



Again, why? I've test-fit SCC low profile cable chains on 19s, and can see now reason not to run them. I've spoken with the service department at the dealer and they agree.

The overall size of 18s and 19s with lower profile tires shouldn't be any different so I'm a bit puzzled by all this.

The front clearance is MUCH smaller between the tires and components on the inside such as the spring perch.

Another finding I have noticed is even though the overall diameter is unchanged, the factory 18's sit closer to the body due to the offset (inside clearance unchanged). Therefore, providing more clearance between the fender and the lateral shoulder of the tire.

Here's the thing. I live in Southern California and with my habits, I will probably only need snow chains put on maybe 6 times a year. The times that the chains are on, is only to get to the ski resort and possibly the local grocery store / shops. I typically only go to Mammoth Mountain, Big Bear, or Mt. High. Mt High almost never requires chains, Big Bear sometimes, and Mammoth is usually during a good storm.

It's 334 miles from my house to Mammoth Lakes. Typically snow chains are required for only the last 7-10 miles. The earliest I've seen it required was starting from Bishop which is 40 miles out, but very rarely does this happen. As you can see, for me, it's such a small portion where the snow tires will become useful and is a disadvantage in the primarily warmer / dry stretch of road before hand.

I'll be a guinea pig and see if any damage occurs to the X3 with my new Thule snow chains. They are of awesome quality btw.

Advantages of the snow chains are:
1) minor hassle, but you have the ability to put them on as you get closer to the resort to know if you need them or the weather changes
2) cost
3) not sure if it's better traction since I'm putting it on the rear and most of the braking force is from the front. forward traction should be better than a set of 4 snow tires though.
4) space, I don't have 4 big tire/wheels taking up my garage the rest of the year.
5) I don't have to swap out 4 wheels two times a year.
6) The majority of my driving even during the winter seasons is still on dry road where the all season tires will perform better.

Disadvantages:
1) Having to put snow chains on when it's snowing on your ass
2) Less steering stability as I'm not putting the chains on the fronts.
3) Being limited to about 30 mph while the chains are on and the road suddenly clears up and you don't need them, but might down the road.
4) Worse braking performance?
5) Possible vehicle damage, I'll report back on this one

[nyalpine90]

i believe u do not need chains on all wheel drive vehicle..if anything you should get winter tires!

[TogMogX3]

Originally Posted by nyalpine90

i believe u do not need chains on all wheel drive vehicle..if anything you should get winter tires!

I agree that under most circumstances Winter Tyres will suffice; however, there are also occasions when Snow Chains maybe necessary even for an AWD vehicle.

However: -

FACT! One should NEVER fit SNOW CHAINS to the FRONT WHEELS of passenger carring AWD vehicles used on public roads. In the event that one is compelled to drive in snow conditions which defeat the X3, fitted with WINTER TYRES & SNOW CHAINS on the REAR WHEELS, clearly you are driving the wrong vehicle............... Buy a snowmobile or better still stay at home.

To all who read this..........If still in any doubt please READ your BMW manual. Ignore the manual and you are taking unnecessary risks.

[jt2]

@TogMogX3:

The legal angle is an interesting one, and a good point. I'd be interested in hearing your perspective on the technical side as well, aside from what the manual says.

@sard:

I think your approach is good. I'm in a similar situation. 90% of my drive to the mountains is through the California Central Valley, for the other 10%, I've dumped the awful LS2s, and changed them for ContiDWS, which seems to be about the best A/S out there for snow. I've also stowed two sets of SCC chains in the trunk. I have test-fit them, and think they'll be fine. I also suspect that I'll never find out - the DWS are damn good.

On the front clearance thing, I'm inclined to guess that while the clearance is tighter, it'll be fine if you just follow the installation instructions and don't go over the recommended speed. BMW is likely making recommendations based on worst-case scenarios where people don't put the tensioners on right, and then go too fast. I certainly can't see how chains on all four could harm the drivetrain.

[sard]

Here are two photos with the Thule XG 12.