Hello all,

Something disconcerting happened before and during a ride this past weekend, and I'm hoping for some input. Here's what occurred:
Being a shrewd observer of the obvious, when I got the tandem down (it lives vertically, with the weight on the rear tire and the front wheel secured by a hook) for a ride I immediately noticed that the rear tire was completely flat. This seemed peculiar as it had been fine when put away, but I figured a slow leak was probably the culprit. So I tried pumping it up as a first step. I heard the air coming straight out and after (too easily) removing the tire found a tear in the tube at the base of the valve. I got new tube out and put it on. I pumped it up to the recommended pressure (95) and set it aside as I put the pump away. One thing led to another by the time I came back from putting the pump away probably 10 minutes had elapsed since I had left the wheel leaning against the wall. I was at the bike preparing it to accept the wheel and… BOOM!! The tire had come off of the rim and the tube of course exploded. I figured I had made some sort of mistake in mounting the tire, but was leery about how loose the fit was. So I got out a new tire (and tube) and put it on. This went on pretty easily too, so I was extremely careful to make sure that it was evenly on the rim. I inflated slowly and stopped several times to adjust to make sure everything was perfect. Once fully inflated (105 for this tire) I bounced the wheel/tire around to see if I could induce any problems that were thinking about showing themselves. Everything seemed okay, so I mounted the wheel, finished preparing and off we went. We rode about 12 miles to breakfast, took about an hour to eat and then continued on our way. Less than 10 miles from there, another boom. Same thing. Fortunately we were going easily, up a mild grade, in a straight line and so there was no real danger. I replaced the tube, pumped up to only about 75 psi, and we carefully made our way home without further incident. So now, I’m afraid to even ride the thing. The rims are the standard Firs that came on the 2002 Santana, and the tires are folding Panaracer Paselas that I got after reading good things about them here on the forum. I started out with a 32mm on the rear, but the spare was a 28, the original size, so while I don’t know the inner width of the rim I don’t think it could be a size problem. Tangentally, we just returned from the Icefields Parkway in the Rockies so I am really, really glad that this didn’t happen while on one of those descents.
I’ve more or less decided that I can’t use those tires on those rims, but this still seems weird. 700c tires should go on 700c rims, right? Can someone explain to me what might be going on here?
And I guess more importantly, what to do going forward? My sweetie/stoker popped in to a LBS to ask advice and as they specialize in Specialized, see about getting some Armadillos, or Gatorskins. When she was explaining the situation, as soon as she said ‘tandem’, the guy said “Is it a Santana?” and when she replied “Yes” he said, “Don’t get the Armadillos. Go with the Continentals.” So he steered her away from their $60 tires to some half the price that they don’t even sell. (you gotta appreciated that kind of salesperson) What does he know that I don’t about Santanas (Fir)? What do you all know that I don’t know about Santana (Fir)?
So I ordered some Grand Prix 4 Seasons because I couldn’t find 28mm Gatorskins with Kevlar beads and I want to be able to pack one as a spare. Only after placing the order did I start to think about the folding bead as a source of the problem. I have searched here and found only one example (with unknown tires) that matched our ordeal almost to the letter, but many saying folding tires should work just fine. Even so, now I’m second guessing myself, and I have some questions.
Are Firs known to be on the small side?
Are Paselas known to be on the large (loose) side?
Are folding bead tires less secured than wire bead ones (all other things being equal)?
If a tire is really easy to get on a rim, is it likely to be blown off?
Conversely, if a tire is difficult to mount, is it less likely to be blown off.

Any enlightenment would be greatly appreciated.

mandd

When you install a tube, do you go all the way around the tire, pushing back the bead to make sure the tube is not pinched? On both sides?

I've never had a problem with a Panaracer Pasela tire, folding or wired.

If you heard a boom, the tube was outside the tire.

My standard procedure is to fill the tube with enough air that takes its own shape, put that in the half-mounted tire, and then start fitting the tire at the valve, using it to push the tube and valve base back up behind the tire's bead. I am pretty careful as I get the rest of the bead over the rim, and if the tube has the right amount of air in it, it seems to work very well in keeping the the tube in the right place. I can't say that I did that the first time as I wasn't thinking about it. But the second time it definitely had my full attention and I was very careful. Interestingly, in both cases the tire bead was blown off of the rim, blowing sealant all over the place. (I've come to really hate that stuff). It really seems to me that the bead just didn't hold the pressure.
Of course I could've made a mistake, no matter how careful I thought I was being. But I don't think so. I've never had this happen before in 35 years of biking and changing my own tires. I have gotten rims pinched by not being careful when I was younger, but not in a long time, and they didn't fail like this.

On what rims did you use the Paselas? Were they super-easy to get on and off the rims?

We run Conti Gatorskin 700x28s (wire bead) and have never had a problem. The Kevlar belt under the tread seems to make them pretty bullet proof and we rarely get flats before the tires wear out.

The rear rim is a Mavic and the front a Sun. The tires are VERY hard to mount. I can't imagine the tire bead ever coming out of the rim on its own.

Just returned from the Icefield Parkway huh? Isn't that the most beautiful country you have EVER seen? We've done it twice and would do it again in a heartbeat. However the climbs up Sunwapta pass are pretty brutal - especially from the south. I agree, I wouldn't want to have a blowout on one of those descents.

Yes, it was amazing. We had high hopes, and it was better in reality. We will definitely go back--it has become one of our favorite areas!

FIR rims as well as Specialized Armadillo & Turbo branded tires have had some independent issues...

The first showed up around 2000 when folks running the FIR rims with both Specialized Armadillo and Turbo / red sidewall tires started experiencing blow-offs and other tire durabilty / failure problems. The 'fix' was a switch to Continental tires. The archives at Tandem@Hobbes are rife with many of the accounts. I'm not sure if they ever fully determined if there was a rim compability issue or not; perhaps someone will know who may have lived through the problem.

The second issue that I recall was a bad run of the FIR rims back in 2001 when a die fell out of spec. The sidewalls of the affected rims would deform & bulge out under pressure where the initial indicator of the problem was unexplained tire blow-offs just as you described. It would be prudent to inspect your rims to make sure there weren't any signs of sidewall fatigue where the sidewall joins the rim bed as that's where the die problem was, i.g., insufficient material thickness.

In any event, the folks at Santana should be able to confirm if the rims that were shipped on your tandem were part of the problematic batch based on a check of your frame's serial number and/or the serial numbers on the rims.

Would get in touch with the 'tana folks and see it they have a solution to your rim/tire problems. Seems the bike shop mech knew what he was talking about!
We run folding tires (Maxxis Re-Fuse 700x25) on Velocity Aerohead rims for 22,000+ miles and never had a tire blow off. I can install/remove tires without tire tools so they are not a hard fit. However, we do use Veloplugs instead of rimtape which gives a tad more room for installing tube/tire.
Usually when we install a new tube in tire, we inflate it with a couple pump strokes and then deflate it. Only after that do we inflate tire to the max, eyeballing the rim to see that tire stays properly seated.
In our decades of tandeming have had 3 tires blow of a rim while riding. One was a Contintental tire (back when they first came out) and the other 2 were tires sent by Avocet for us to test ride. Both Avocets blew off the rim . . . one front and one back, in less than a hundred miles.
Some tire/rim combos seem to be more prone to problems.
BTW, we do not use sealant in our tubes; tried it and felt it was too messy when you did have a puncture that would not seal properly.
Be thankful the blowups did not cause you any worse problems.
Pedal on TWOgether!
Rudy and Kay/zonatandem

Last summer we rode from Banff to Jasper & back. Four days up and three days back. We used Brewster Bus Lines as our baggage transport. It worked great! Did you ride up & back? How was your weather? Did you stop at Lake Louise and Moraine Lake?

mandd - back to tires - After some consideration, we've settled on Conti Gatroskins. I think Bill McCready claims these were developed jointly between Santana and Continental specifically for tandems (not sure on this). I imagine there are other tires with comparable durability.

With tires, I'm sure there's a tradeoff between "performance" and durability. I want to minimize the chance of failure. I'm sure that the Gatorskins are not the lightest or most supple tires but they have been quite durable for us. I want as much peace of mind as possible descending at 50+ mph.

I believe what Bill did was guarantee to spec. the Gatorskins as Santana's OEM tire to support an EOQ that made design & production of a 700x28mm (i.e., tandem / touring) version of the existing Continental Gatorskin feasible.

We obviously aren't as fit as you!! We didn't ride the whole thing--couldn't have. In addition to riding the tandem we also hiked, kayaked and mountain biked so we didn't put a huge amount of road miles in. We drove there (from Minnesota) so we had a car the whole time and stayed several places from Banff to Jasper, using where ever we stayed as a base camp and doing day trips from there. We stayed at Lake Louise a couple of nights (the town, not the big château) and hiked and mountain biked there and biked the old highway (1? 93a? I forget) to Banff and back on a day trip. Then we stayed at Emerald Lake, but only hiked and Kayaked there. We were going to stay at The Crossing for a couple of nights and use it as a base to go South one day and North the next, but disliked the place so much we went straight to Jasper and extended our stay there. We stayed 4 nights just South of Jasper, and biked to Maligne Lake from there one day and to Athabaska falls another and Mountain biked another. We also had some down time.
The weather was all over the place. (7/2-7/11) We were prepared for pretty much everything so it wasn't a problem. Most days started out nice and then clouded up. It rained at some point in the day more often than not, but we never had a day that was more than about 25% rain. Temperatures tended to reach around 70 most days with a couple days being sunny and approaching 80. On the way back from Maligne Lake to Jasper (about 35 miles, almost all down hill) we were either in bright sunlight or rain, sometimes fairly heavy. You could see it coming (and going). We hit our current record of 54mph (on those damn Paselas, no less) trying to stay with a patch of sunlight and ahead of some rain.
All in all, it was a wonderful trip. So much so that we were kind of crabby when we had to leave. I'm not sure when, as it will take some time to pay off the credit card, but we are absolutely going back. It was a truly amazing place.
To everyone else, this is a fabulous place to ride. If you are considering it, I recommend it without reservation. I found the mountains to be more enjoyable than the Rockies in CO, WY & MT because they weren't so arid. The scenery just never stops. And the roads were great. There was plenty of room to bike and as the whole thing is a parkway, speed limits are low and cars tended to be more polite than on normal highways.
And to top it off, we got engaged there (!), so we *have* to go back and celebrate once in a while.

I will definitely inspect the rims. Thanks very much for the info. Do you know what, if anything, Santana did to rectify the situation with the out-of-spec rims?

Thanks to everyone for the replies! (how did people survive before the internet?)
As long as the rims seem okay, I will try the GP 4 seasons when they arrive. If they seem "iffy" I will probably exchange them for some wire bead gatorskins, and figure out something else to do for a spare.

Thanks again!

mandd

As this weekend is forecast to be beautiful, and as the Continentals aren't going to arrive until Monday...
I also have a pair of Kenda Kwests (28mm, wire bead) that I have mounted on a spare set of (non-tandem) wheels that I had intended to go on a commuter project that has yet to get off the ground. I hadn't thought of them for the tandem (they seem kind of hard and cheap) but... Does anyone have any experience with these tires on a tandem?

Oooo, and that reminds me of another thing. Last one, I promise. Those Kwests are mounted on some old Shimano wh-540 wheels. Those were the kind that look just like the Santana/Shimano sweet 16s. Does anybody know if they are susceptible to the tension and cracking problems that the Sweet 16s seem to be known for?

Thanks!
mandd

Not a clue. I just recalled and verified that there were some issues discussed back in '02 where one of Santana's dealers offered up the explanation of the flawed run of rims.

Again, you can contact the folks at Santana with your frame's serial number and they should be able to confirm if there are any issues that require your attention. In fact, I wouldn't even introduce the internet discussion... just tell them the year, make, model of your tandem and let them know what type of rim and tire you were using. They'll take it from there as I'm sure your situation will not be new to them.

Take a really good look at the tires that blew off. I had one blow out that ripped some rubber off the tire at the bead and it would not stay on after that.

Also take a good look at the rim bead grove. Some rubber may have been left behind. This may explain why other tires had problems.

I've been trying to get some Conti Gatorskin 700 x 28s locally and 2 bike shops say that they're having trouble getting any Continentals recently. Something about a European shipping strike and/or a change in the way Continental does it's distribution. Any similar experiences elsewhere?

We purchased our Santana in early 2001. It came with 700x28 wire bead Continental Ultra 2000 tires. After wearing out these tires we decided to switch to the same tire, but in the foldable version. Both versions of these tires were pumped to 120 psi. Our problems were nearly the same as yours and we quickly switched back to the wire bead version.

At 2500 miles we found small cracks between the spokes of the rear Fir rim. It was replaced by Santana but we had to pay for shipping one way. By the end of that first year (5000 miles) we found small cracks between the spokes of the new rear rim. We speculated that the rim may not have been taking the stress of the disc brake. Rather than pay for shipping again, on a rim we didn't trust, we switched to Velocity Dyad rims. With the new rims, we were able to go back to the foldable version of the Ultra 2000. Of course, they no longer make that tire and we are now using wire bead Gatorskins.

Until you are ready to change to a new rim, stick with the wire bead tires.