I've just made an appointment to have my 08 Mini tinted tomorrow. I asked about having the sunroofs tinted and my tinter strongly suggested against it. He has evidently seen broken glass because of the heat buildup. Has anyone seen this? My other question is whether or not there is a way to make the existing sunshade denser? Different material, etc. This would allow the sunrooof to still breathe while keeping the interior cooler. Oh, by the way, I live in Florida and it does get pretty hot down here.

Thanks,

Scott Davidson

 

This seems to be a concern due to reports that some tinted sunroofs explode. How common is this really? Perhaps you should ask the Tint shops since surely any significant failures would get back to them and they wouldn't want the liability.

I have formed my own conclusion based on reasoning as follows:

First a little background:

Tempered glass has built in compressive stress created by cooling the outside layers quickly before the inside. When the inside cools it shrinks and pulls against the outside layers with a wallop. As a result tempered glass is 4-5 times stronger than ordinary glass and the best choice for exposure to uneven heat that can cause high stress. This link says the surface of tempered glass has a 10,000 psi compressive force built in to achieve that strength:

http://www.aisglass.com/flat_tempered.asp

Now for a hypothesis:

• Sunroof glass is really not much different than side windows - both are tempered
  
• Tempered glass with a defect, scratch etc are just time bombs waiting to explode, and not necessarily in need of a big stress to do so
• Side windows can get just as hot as sunroofs with sun exposure
• Examples of spontaneous sunroof glass exploding are fairly common, few of these are reported to have added tint, at least some do not have tint film
• Examples of spontaneous side windows exploding are at least common, though reports seem less prominate. Some have tint, some not.
  
• A possible reason for more attention to sunroofs is there is no obvious way for them to have been struck , and if they occur while driving create an even bigger surprise

The relationship between adding tint and an increased glass breakage has not been established. Even if it increases the probability it cannot be a major factor since they occur even without tint.

It is possible that a different coeffecient of thermal expansion for the film vs the glass could cause some slight stress due to bowing but this hardly seems significant for the 10,000 psi compressive force at work between the layers.

I feel confident that adding tint to my sunroof is no worse than adding it to side windows. If I am wrong then only if the glass is already defective would I expect it to break. I don't want defective glass on my car anyway and I believe the film could help reduce the surprise effect if it pops.

Now if I can just get my MINI delivered so I can start the experiment!!

 

I had mine done with Huper Optik (German) 40% ceramic tint. I have used this on 2 vettes with black interiors and now the MCS. Compared to any other film on the market, this film transmits almost no heat through it. You have to see it to believe it. I'd give this consideration. It's expensive compared to normal films, but I think it's worth it.
Fig

 

Thanks for the quick response. The tint I'm getting is Pinnacle by FormulaOne. Glad to hear of the superior heat rejection...

Thanks,

sd

 

yeah with the hi-tech upgrades and refinements to these cars the one thing bmw has not addressed- how to shut out the sun so the a/c doesnt have to work so hard

 

I would really like to see someone come out with a replacement sun shade that is fully opaque. That aside, you could always get a perforated sunroof decal. If you don't want a flag pattern or whatever, you could just do white or black. It won't cut out the light completely but it should cut down on light & heat by 80% or more.

 

Wow, I didn't know that tint could possibly contribute to the exploding sunroofs I've heard of.

I had mine tinted 35% which is legal here in NC. It was dark enough so I changed it to 20%.

It definitely helps keep the heat out. I can't say about heat because I bought a stupid carport to pull my car under during the day at work.

Mark

 

I did 5% (limo tint) on the sunroof and 20% all around and can see out perfectly and not much glare coming in.....if I want glare I open the sunroof. We did my father's sunroof on his mini with 20% a year ago and he wishes he went darker too but to each his own.

G'luck with your decision.

 

I agree... thus the reason I wish Mini would have made a screen or sliding cover that blocks out the entire sunroof.

Ridiculous....

Mark

 

I'm thinking of Huper Optik 60% windshield, 50% all other windows, and not sure about what % for the sunroof. How did you decide on 40% for your sunroof? Also, how about your other windows?

Thanks.

 

FWIW, I have tinted alot of mini suroofs w/all kinds of films. I have never had one come back because it cracked.

 

That's good because I wasn't about to rip off the tint...lol. Sounds more like the exception than the rule.

Mark

 

I think I'm gonna go 5% sunroof, and 27% all around to be legal here in SC. Try to keep the heat down, and can always open the sunroof if need be

 

Smart smart smart. 5% is the way to go on the sunroof!

 

I'd used the 40% before and it was a good compromise, given the tinting of the glass from the factory. Obviously the darker you go, the less heat transfer there is. Virginia limits you to 50 on the front windows, and I didn't want the overall appearance from front to back to vary too drastically like you see on a lot of cars. This is more balanced. 40 on the sunroof cuts down the heat some but still gives me good visibility out.
Fig

 

Thanks. I'm going to do 40% for the sunroof. I made an appointment Tuesday with Art-of-tint in NYC. The installer mentioned he didn't like putting anything darker on the sunroof because it will heat up the glass itself and possibly break it. He's only had one tinted sunroof break in his 15 years, and he said it was a very dark tint. The tint may not even be the culprit, like the guy whose un-tinted mini cooper sunroof recently shattered.

 

A cheap fix for the overpowering sunlight coming in through the shade:

open the sunroof and place a small dark color cloth or towel (size of a dish towel) on top of the sunscreen...and then close the sun roof. Works perfectly!

 

As ridiculous as that sounds it's not half as ridiculous as the fact that Mini only has a mesh screen up there i the first place.

 

Got my car done this past week 32% Carbon tint all around and 20% on the sunroof. Works well with taking down the heat and I can still look out roof on starry nights!
Talked to many local tint dealers here and Georgia and only one cautioned tinting sunroof glass. Also spoke to Mini sales and service at local dealer and they said they have many of their new mini's sunroofs tinted and hadn't had any shatter incidents.

Here are some pics

 

The first company I approached refused to tint my sunroof, but the dealer farmed it out to someone who would. I don't know the percentage, though. The MAs there said they hadn't heard of anyone's roof exploding, although they were aware of the possibility.

Max, you say that window breakage is "fairly common." Other than my own sunroof breaking due to crash impact, and the rear window breaking for unknown reasons on my father's car about 30 years ago, I haven't heard of ANY windows spontaneously breaking. And I've been driving for 40 years, nearly all of that as a member of various car groups.

 

I just based my input on how common it is after a web search. It isn't hard to find reports of glass sunroofs shattering in many different model cars. I don't see people reporting it due to tinting or heat nescessarily. Some models seem to have a rash of reports like the link below for Renault.

Compared to the number of cars made with sunroofs the reports are probably still a very small percentage. If it were even 1% that would be thousands of cars and if you were to number the reports on the web I think it would be more like hundreds. That is more common than I expected, but still unlikely enough not to be too concerned.

http://www.carsurvey.org/viewcomments_review_65329.html

It maybe a glass quality problem,the second link describes how inclusions of impurities can cause the glass to fail.


http://www.prelco.ca/pdf/fiches/Prel-Gard_A.pdf

 

i like the white 3rd brake light?

 

All of the reported sunroof factures are on cars that bolt wholes penatrate
the roof. not a problem on the mini. doug

 

Seriously, I think the mesh screen is one of the greatest features of the sunroof desgin (I also loved it in my A3, very similar design), I love the light it adds, love the fact that I can open the roof and still block out a good portion of the sun, and bugs. I personally think it blocks out just enough sun on most days, and makes this sunroof so much more useful than the average one you get in most other vehicles.

I really don't get why people tint the sunroof, it seams to me that it takes away a great function of it, especially at night, and on those sunny days that it does really bother you, you can get a sunshade that fits in, and its easily removed, so you don't have to give up anything.

As for tint when I had the A3 done with Huper back in 2005, the installer also said to me he would advise against tinting the roofs (he's one of the top tinters in the country, has a bunch of awards and such, did Derek Jeter's Saleen right before my A3), as it was a similar design to the Mini, and he had seen cases of them exploding when tinted (of course this would have been the R50/53). I didn't bother to ask him this time around because I really never found the need for it in the A3. There is probably very little chance of it actually happening though, but its interesting to see that the experts advise against it.

 

I tinted my sunroof with 5% Limo and live in good 'ol Texas where the temps average in the triple digits during the Summer months. So far, no problems. I think it keeps my car at least 10-20 degrees cooler. I do 'flip' up the sunroof when it's sitting outside though. Just leave it in the 'cracked open' position to let air circulate during the day.