590mm Sun CR-18 + 590mm Panaracer Tufflex is a crime against humanity
 

This is the worst tire/rim combo I've yet seen. The only tire levers that survive its tightness are heavy-duty solid steel levers with no plastic cladding. Of course, this will put some nice big gouges in the aluminum rim while wrestling with the tire, but it sure beats snapping expensive clad tire levers.

I thought the Kool Stop Bead Jack was an infallible way to install tires on difficult tire/rim combinations. Not so, apparently. Now I'm nursing a shrapnel wound from the fiberglass-reinforced plastic that exploded under load. Funny when a spoke replacement and wheel truing is much more straightforward than removing and replacing a tire to access the spoke bed.

Just wanted to register this comment in a searchable place for anyone specing out a 590mm wheelset. Comments or other bad tire/rim combinations welcome.

Hmm. I think the CR18 are about the only game in town for a double wall 590 rim too. I've built a couple of them and put Schwalbes on them. Don't remember that being a struggle.

The tires will probably get a little looser over time. There are tricks for mounting tight tires. It takes patience. And it will hurt. And it will put callouses on your thumbs.

I can't fathom why people put up with outrageously tight tire/rim combinations. If you're paying a premium for performance, one feature that should rank right up there with weight, pressure and other considerations is the ability to change a flat easily on the road.

It should be easy enough that you can do it in the dark with cold half numb fingers while it's raining.

I could under stand tight tires for racing if it led to a performance benefit, since you won't be changing it on the road (a paid mechanic can do that), but for those of who have to change our own tires ease of doing so is one of the first things I consider in choosing tires and rims.

whenever i see sun rhynolite or cr 18 rims come up i steer them away due to difficult tire mounting. they are inexpensive rims but generally other options are available. to the OP use the thinnest rim tape you can find

Yup.

FLYcrash, I'm new to the CR18 rim and yes, it was the most difficult rim I've had yet WRT mounting/unmounting a tire. I broke a Pedro's tire lever, but the Park tire levers were okay in the end. It's also the first rim I've ever had to use all three levers of a set to remove a tire.

Brad

Depends on the rim size as well. I have a CR-18 in the 451mm (20") size and it's the easiest rim I've ever had for changing tires. But the one I have that's 622mm (700c) isn't nearly as good for that. I second the suggestion to use thinner rim tape if you have a rim/tire combination that's too tight. Conversely, thick rim tape is good if the tire fits too loosely and you're concerned that it might come off if you get a fast flat.

The CR-18 in 584 ISO is no better. As I recall, Harris Cyclery had something on their website about Sun missing the mark on the sizing, and at one point it was so bad they stopped carrying them.

Wordbiker, I guess that's all settled as I recently bought these from Harris, I forgot to add earlier that mine are 622 mm.

Brad

Thanks for the comments. I appreciate the tips about Rhyno Lites and about messing with the rim tapes. The bike is a vintage 3-speed Schwinn my girlfriend uses to commute to work (a short haul, just a couple miles). In the case of a flat, walking the bike wouldn't be catastrophic. I'm not using this combo for performance, I'm using it because these were the parts I bought when I initially built her the wheels 3-4 years ago.

From the various experiences with different sizes of CR-18, it sounds like the folks at Sun may not be so worried about keeping things tightly in spec.

The spoke repair and tire remounting are done (courtesy of those heavy steel levers), and the bike will be back in action. But going forward, sticking with the combo is starting to seem like false economy given that I've now broken a moderately priced tool like a Bead Jack. If she gets a flat, I may spring for a pair of Schwalbes, which sound potentially looser (thanks for the tip, Dan). If spokes keep breaking (this was the first wheelset I ever built...haha), it might be time for new rims. Maybe some 650B Velocity Synergys. Those are some great rims, though I'd be getting further and further from the 597mm wheels the bike was designed for.

Thanks again, and take care. :)

Using a thinner inner tube can help, too.

Forgive the stupid question, but how?

The tube is well up into the tire, and isn't ever (or at least shouldn't be) between the tire and rim. So how can it make a difference in a situation where the issue is the difference between smallest diameter at the center well of the rim the bead diameter of the tire.

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There are shallow rims on which it's somewhat difficult to mount any tire, and there are tight tires that are harder to mount on any rim. The combination of both is a nightmare.

I run into this often, the last time being when I stopped to help a damsel in distress. She'd gotten a flat, but was properly equipped to take care of herself, with a pump, spare tube, tire levers and the required knowledge. She shouldn't have been stranded, but...

Her local shop sold her and installed one of these ultra-tight tire/rim deals, which worked fine until she flatted. I was finally able to get her going, but what should have been a 5 minute job took over an hour.

use velo-plugs.

seriously.

Interesting. I was just planning on getting some 590 CR18 rims. Not too many choices in double wall rims in that size. I've been happy with the CR18's I have in the 622 size with regards to tire mounting.

I've read elsewhere that the 584 (650B size) Sun CR18 rims that were on the market a few years ago were notorious for being a tight fit.

I think the biggest problem is that the tolerance stack up for rims and tires sometimes work against each other. Tires and rims have manufacturing tolerances and due to the nature of mass production by various companies I imagine that the tolerance stack for a particular tire/rim combo sometimes makes things very tight fitting. For example, a particular rim is on the big side of the tolerance and the tire is on the small side of the tolerance. Both might be within their respective tolerance, but it makes fitment a real pain.

To the OP, I know that tires aren't cheap, but have you tried any other 590 tires to see if it is the rim or the tire?

Hi krome,

I haven't tried other tires. As I mentioned, I'll likely try the Schwalbes if any punctures happen.

My guess is that it's the rim, given the major out-of-spec issues with the 584mm CR-18s and the above widely varying experiences with CR-18s of different sizes. Also, I've used Panaracers (other models, not the Tufflex, admittedly) on quite a few bikes on a variety of rims and literally never had a major fit problem.

To others: Thinking about the rim tapes and velo plugs, I realized I don't understand why that would help. I'd imagined the tire/rim fit as the hoops in the tire bead meeting the lip in the rim channel, fairly remote from the rim tape. What am I missing?

FLYcrash, I don't think my rims are out of spec. as the tire seats perfectly when inflated. The issue as I see it is my wire bead Forte Gothams (Panaracer) have little flexability and there is essentially no channel for the off side of the bead to be worked into in order to gain any extra clearance. Just an unfortunate combination, not a deal breaker.

Brad

I just built up 2 CR18 rimmed 590 size wheels and fitted the Panaracer Col de la Vie tires on them. Velox tape, schrader tubes, the tire is a 40x590. I could get the tire on without any tools. Getting it back off the bead, I probably won't be able to do so without a lever, but I'm very happy with the way the tires went on the rims. For me, Sun CR18 + Col de la Vie is a nice combo.

Edit: The tire is listed on the sidewall as a 40, it is roughly 35mm wide on the CR18 rim

krome, how do the tires ride? Do the wheels make the bike feel almost modern?

They ride great. I'm not sure how to answer your last question. I have cheapskate retro-grouch tastes. No carbon fiber, no modern race style bikes, so I don't know what you mean by "almost modern" I have an old Raleigh mountain tour Tamarack in 650b, I like it except it is heavy. The Raleigh Marathon I have the 650a tires on is an improvement. I went from 27" to 700c. Tried a 35mm wide 700c and the ride was nice, but no room for fenders. Dropping down to 590 iso with the fat tires still leaves plenty of room for 50mm honjos.

It is good for the dirt roads in the area. There is usually some gravel mixed in for good measure. It is now my town and country bike. Still have the fenders to do.

Oh, since you're using 650A, I assumed you were talking about an English 3-speed or similar bike.

Yeah, if you aren't familiar, the Raleigh Marathon is a low (mid?) touring/sport bike. Mine is probably from the early '80s. The stock setup was for 12 speeds, drop bars etc. I like it because it is relatively light (has triple butted chrome-moly main tubes) and just a nice style and color (mine is dark green w/silver highlights). It has stamped lug construction (+2 extra grouch points! -1 point because it isn't investment cast lugs) and all the eyelets I want for fenders and rack.

650A is my 650B alternative. Cheaper rims, cheaper tires (usually), and most of the benefits of 650B. 584 iso has more dirt oriented tires available, but I'd say that 590 iso has a good selection on the non-dirt end when you take into account some wheelchair tires that are available in that size. If you have enough brake adjustment (3mm difference) they are practically interchangeable.

I'm liking the Col de la Vie tires. They are cheaper in 650B (irony?).

Nice idea! Can we see pictures?

Sure. It will be later in the week, I've got to remedy something first. I wish I had taken a photo before I did anything to it.