bark_eater 

I picked up a wheelset that has narrower front rim. They seem like their the same vintage and patina, so one might assume that the pairing might be intentional, though parts pile inventory would of course be more likely... Thoughts?

Charles Wahl

I think I remember reading somewhere that it was more important, for ride comfort, to have a wide tire in front than in the rear. Just sayin' -- it might be misinformation.

randyjawa 

The ride quality will improve in one area, feel but diminish in another area, comfort. Why?

The heavier the wheel rim tire and inner tube, the more clumsy the feel. Prove this to your self. Pick up a wheel and, holding the axle ends, tip the wheel from side to side. There will be little or even no resistance. Now, spin the wheel and, still holding the axle ends, repeat the tipping exercise. You will immediately feel the resistance thanks to the gyro effect imparted by the spin factor. With this in mind, when the bicycle with the narrower rim will seem to be and will also, marginally, be more responsive and feel lighter.

As for the comfort factor, a narrower rim will, probably be fitted with a smaller tire, reducing the cushion effect, thus negatively impact the comfort factor.

Was this original issue from the bike maker? I really do not know but I do know that in all the bikes that have come my way, I have never seen a bike issued with different width rims (at least none that come to mind).

Hope that is a help.

Straightblock

My guess would be that the rims matched when the wheelset was new, one of the wheels was wrecked or cracked, and the owner replaced the rim with whatever was available.

iab

The most entertaining advantage it could have is to bring people out of the woodwork to pontificate a performance advantage when in reality the only advantage is you have 2 wheels for your bike because something happened to the matching wheel.

Soody

Not relevent for a road bike but if you run wide gravel or mtb tires on narrow/narrowish rims the rear one is the first to become a problem because it will squirm in corners.

scarlson 

The back wheel is less strong than the front wheel because of dish, so it needs a beefier rim?

I think more likely one of the wheels was messed up or stolen, so another one was gotten.

Schreck83 

Wheels end up being consumables. Tires/tubes for sure and if the rim gets whacked, there’s a good chance the hub goes with it.
Do your hubs match?

Mr. 66

There would be a smaller patch of contact, if that means anything

wrk101

No one paired Mavic rim wheel with an Ambrosia rim wheel. Something happened, like a crash. I often find bikes or even wheel sets where the wheels do not match.

cyccommute 

I wouldn’t assume that the pairing was intentional. Those are very old rims but not necessarily of the same age. The process that creates patina reaches an equilibrium at some point so that two items of slightly different ages can appear to have aged the same amount. Most likely the front wheel was replaced for a myriad of reasons from a wheel being stolen to damage to loss to wear. There’s no advantage of a narrower rim other than weight.

Saudadeii

Sometimes a mismatched wheel set is just a mismatched wheelset.

mstateglfr 

This wheelset is the same concept Merckx used late in his career to regain a bit of the edge he had lost. The front wheel is narrower for aerodynamics and the rear wheel is wider for comfort.

...or its just an old mismatched wheelset because someone I. The last few decades broke or lost a wheel.

The Golden Boy 

I'm going to get a narrower front tire for one of my bikes so it clears the fenders more safefully. The rear fits 35s swell... the front... It "fits." Sorta.

I also know there were tourers that came with a 40 spoke rear wheel and a 36 front- I guess, assuming more weight in the rear.

stardognine

I'm gonna just come right out & say it, mismatched wheels are not a wheel set. A "set" of wheels means they have the same parts, rims, hubs, & spokes. And presumably, were built at roughly the same time. 🤔😉

There's certainly nothing wrong with using mismatched wheels, pretty much all of us probably have done so. But calling mismatched wheels a set is a minor crime, punishable by flogging, or at least public ridiculing. 😁😉

That's my opinion, so it must be right. 😁😉

Lombard

A wider rim does not necessarily make a stronger wheel. It has more to do with build and a higher spoke count.

I'm guessing the mismatch was due to a rear wheel failure and replacement.

scarlson 

I don't agree. All things equal, a wheel with a heavier rim, with more metal in it, will be less likely to break spokes than one with a thinner rim. Dish also matters a lot. Dishless tandem wheels can be very strong in spite of a low spoke count.

First, I used to tour on a 36 spoke rear wheel made with a Mavic MA3 rim (470g weight), and broke three rims and ten spokes before lacing the same spokes and hub to a Rigida Sputnik (745g weight), and it has not had any trouble under the same conditions. Same builder (me), same spokes, same hub.

Second, Look at Santana's tandem-specific Shimano wheels, which only have 16 spokes, but are dishless and have special, heavier rims. According to Santana, they were subjected to the same mechanical test trials as Santana's 40-spoke wheels and the 40-spoke wheels broke first.

I would also love to have more spokes, yes. But above 36 you get into specialist tandem components. Heck, even getting 36 is hard sometimes. I put an ad up looking for a 135-spaced silver 36h rear cassette hub and have had no responses in two weeks. And even tandems are going to heavier rims with fewer spokes now.

SurferRosa

Then everything is a consumable.

scarlson 

The front brake often gets used more than the rear. If they are the same hub, maybe a new rim got swapped in after the rider braked through the front rim.

I'm having fun speculating as all these things have happened to me.

79pmooney

That Second +1. I build my rear wheels with DT Revs or equiv. (2.0-1.5-2.0) on the NSA and Competitions (2.0-1.8-2.0) DS. But my fix gears get just the Revs on both sides and are better wheels. Much stronger, fewer issues and feel much more solid on right hand corners.

canklecat

Nope. Back in the day there were all kinds of theories about wheel diameters, rim widths, crank lengths, etc. But wind tunnel and quantitative testing methods debunked most theories, or explained why some did indeed work, although not always for the reasons original speculated.

For example, wind tunnel testing indicates that -- if we want to wring out every nth of a degree of performance -- tire and rim width should be carefully matched. So while my 700x25 tires are comfy on my skinny rims intended for 700x18 or so tires in an era when 700x23 tires were considered "fat" for road racing... I'll never be strong or fast enough for it to matter. It might be a factor for an elite level rider on a closed track chasing an hour record.

Subjectively, I've found that if tires are too wide for the rims, the ride can feel splashy on fast curves on rippled or rough pavement, as the tire bulges out beyond the rim and loses some road feel. That bothered me a bit a few years ago when I was strong enough to push my limits. My legs are so old and sluggish now I can't remember the last time I was pushing any ride hard enough to notice minor differences in handling. Maybe 2019 was the last time my legs were strong enough for that, and only on occasion. 2017 -- pre-cancer and being hit by a car -- was the last time I was consistently fairly strong and noticed a slightly splashy feel from my 700x25 tires on skinny, lightweight rims.

Speaking of which, some of those techie late 1980s rims, like the Araya CTL-370 hard anodized, could come pretty close to pro level performance in a clincher format, but at a cost. Those lightweight, low profile rims needed more frequent truing, and tending to be a bit fragile. My CTL-370 and comparable Wolber Super Champion Alpine clincher rims finally cracked and spokes began pulling through on rear wheels after many years of use. The front wheels are still okay. I'm saving both in case I ever get a notion to rebuild to factory specs. But I've mostly moved on to sturdier, higher profile and heavier Mavic rims.

Anyway, that quirk could explain some mismatched wheelsets on bikes of that era.

cyccommute 

Explain how that would work. What is the heavier rim doing that the lighter rim won’t?

Rim strength has very little to do with wheel strength. You can take the strongest, stiffest rim around…a steel one…and build with weak spokes. The wheel won’t be “strong” because the spoke are weak. Alternatively, you can take the strongest spokes…2.3/1.8/2.0mm triple butted spokes…and lace them to a “weak” rim and still have a very strong wheel. The spokes are what breaks, not the rim. The rim isn’t really attached to the spokes. It is free to move on the spoke during riding and does so as each point on the rim approaches, is directly over, and passes by the contact patch. The rim deflects upward, decreasing tension on the spoke Go into a corner and the spokes are still the part that takes the brunt of the lateral forces on the wheel.

I always build with the lightest rims I can find and seldom have wheel breakage issues…even on loaded touring bikes.

While the Santana wheels look interesting, I think you are misrepresenting what they do. First, the rims aren’t heavier. Santana says

Second, the spokes put different stresses on the rim than conventional spokes do. I would question the longevity of the rim sidewalls with the spoke pulling on a weaker part of the rim than conventional spokes do. They say they are reinforced but that is still a bad place to put the spokes.

The key isn’t necessarily more spokes but better ones. The triple butted spokes, suggested above, are about the equivalent of added 4 to 8 (perhaps) spokes to the hub. They are significantly stronger than straight gauge spokes and don’t require proprietary rims to build them. Most every hub is drilled to pass a 2.3mm spoke through the hole in the hub because that’s the increase that rolling on the threads puts on the spokes. The heavier bend increase fatigue strength about 50% which makes for a more durable wheel.

scarlson 

I am merely relating my experience. I may be an exceptionally heavy tourist. We did carry a pétanque set with us at one point. And a couple of lawn ornaments we had found. Small BBQ also. Tried to make ourselves at home in our campsites over the year or so we spent on the road. I will explain below why I think it happened this way.

My hypothesis for my experience is that heavier rims are less flexible so they spread the load out. You mention the spoke tension decreasing above the contact patch. Yes. I think this effect is more spread out on a heavier, less-flexible rim. Thus, more spokes share in it so the overall effect on each individual spoke is lower. Also, often I find I can build with a higher tension if I use a heavy rim. This may help to insure nothing ever comes completely loose under any extreme circumstances (e.g. hitting a poorly graded cattle grid with a touring bike carrying a pétanque set and a bottle of Grand Marnier and a Campingaz grill in addition to the usual sundries). We pulled spokes through the MA3 rims, completely destroying them. We saw cracks developing in the A319 rims a couple times. But we never broke a Rigida Sputnik. We also broke many spokes with the MA3, but not with the A319 or the Sputnik. Not sure what else could be responsible except the extra metal in the rim.

Seems to be working for them in spite of it all. I would like to know the weight of their 16-spoke rims, as well, but I can't find a weight figure to compare them to the usual ~500g Mavic fare available in 40-hole. I held one in my hands at a trade show a while back. It felt like a touring rim, certainly. That has been my experience with a lot of these modern low-spoke-count deep-section rims. They are heavy.

I agree with you, I like triple butted spokes for all these reasons. 13/15/14ga, the equivalent of 2.3/1.8/2.0, sure. But I don't like them enough to rebuild an existing wheel with them. They are nice but they are pricey! Any new wheels I build are usually with the Sapim Force unless it's a budget build.

cyccommute 

For the most part, the extra metal in the rim is taken up by the increased volume of a wider rim. The walls of the rim aren’t any thicker and the force from the spoke tension is concentrated in the same area. The area around the spokes is what is going to take any force that the wheel experiences in impact and having very similar thicknesses around the spokes doesn’t increase their resistance to cracking just because the rim is wider.

Mavic MA3 are an old model that has a history of cracking…I’ve broken some. I would suspect a metallurgical problem that seems to have been fixed in later years with different models.

Just going by what Santana says in comparison to other rims. That said, the rim, the hub, and the spokes are proprietary and, I think, come from Shimano. Shimano has a very poor history of supporting technology which could make replacement difficult in the future. It’s an interesting design but likely to be a technology dead end in a few years.


I prefer to use the diameter measurement over gauge measurement. It’s less confusing. There are a number of spoke manufacturers that make triple butted spokes that aren’t all that expensive. It also depends on where you get them from. Pillar (sold through Bdop Cycling) are relatively cheap at $0.89 each. The deal of the Intertubz, however, has to be DT AlpineIII from Rose Bikes out of Germany. 0.41€ or about $0.41 each, US. That cheaper than wholesale. Yes, you have to pay shipping but, even with shipping, the cost is below wholesale in the US.

bark_eater 

Who ever was riding this bike put most of the wear on the 52t big ring. The front brake pads may have been replaced also, I'll have to check the parts pile.