An Interview with Tech Guru and Bike Builder Lennard Zinn On 32-inch Wheels

Jim’s Tech Talk

By Jim Langley

A few weeks back in our coverage of the early season shows, including The Sea Otter, I wrote about the growing interest in and use of 32-inch wheels, a relatively new wheel size. In my comments I mentioned that Zinn Cycles was one of the companies using 32-inch wheels.

After that article, Jan Heine on his René Herse bike company blog published his thoughts on 32-inch wheels based on their testing. You can find that here: 32″ Wheel Momentum: Are Heavier Wheels Better?

Reading Jan’s take on it gave me the idea to reach out to Lennard Zinn at Zinn Cycles since I had mentioned his 32-inch wheels bikes in my piece and also because he’s a fellow mechanic, journalist and friend.

What follows is an interview between the two of us. I sent the questions in an email and Lennard replied beneath them with his answers. I start with my thoughts on 32-inch wheels and mention Jan Heine’s column so that Lennard knows I’ve read it. After that the conversation begins.

By the way, if you’re wondering why Lennard isn’t on Velo anymore it’s because he’s moved to Substack. You can find his Q&As now at this link: https://lennardzinn.substack.com Also, if after reading Lennard’s comments you’re considering ordering one of his custom Zinn bikes, here’s where to start: 

https://www.zinn.bike

Lennard Zinn on 32-inch wheels

Me:

Hi Lennard, It’s been a long time since we were in Amsterdam covering the Shimano event together, that was a fun trip. 

Lennard:

Yes it was! You and your Bike Friday riding right out of Schipol airport!

Me: 

As I mentioned in the previous email, I would like to get your take on the pros and cons of 32-inch wheels, which were one of the big tech trend stories coming out of the Sea Otter. 

Jan Heine on his René Herse blog recently wrote about how their testing shows that larger wheels do not actually roll over rough terrain more smoothly and are not faster either. As I understand it, their position is that it’s the tires that make the difference in smoothness and speed not the wheel size.

Also, they say that the fact that 32-inch are heavier actually means they’re slower to get up to speed and it’s more difficult to keep your speed. They say that the additional weight can make handling sluggish too.

I understand and appreciate what they’re saying. It’s what people said about 29ers when they came out. Yet I remember how much better 29ers felt when they arrived on the scene. Yeah, they were heavier but they felt/feel more lively and easier on most terrain, technical, climbs, downhills, even on the road getting to the trails. And, I don’t think anyone riding 29-inch would want to have to go back to 26-inch.

So I wanted to get another expert’s opinion on the pros and cons of 32-inch wheels – and I thought of you since I believe you at Zinn were among the first to start making your custom bikes with 32-inch wheels. Which would mean not just building these new oversized wheels and all that was involved in that, but designing frames for them too.

I remember how as 29-inch wheels became popular, bike companies improved their frames and suspensions and the bikes rode better and better as the total package improved. Since you’ve been building bikes around them I’m sure you know a thing or two about that too. 

Below are a few questions for you. I appreciate your help!

Lennard:

First, you might like to read this Substack post I did in early March: 

https://lennardzinn.substack.com/p/why-use-32-or-750d-wheels

Me:

Thanks for the link Lennard!

Me:

How long have you and Zinn been building bikes with 32-inch wheels?

Lennard:

The first one I remember was in February 2020, when we built a titanium e-bike with 32” wheels (and a Bosch Gen. 4 motor) for 6’11″ Jusuf Nurkić. I believe in proportionality between the rider and their wheel size, so it took a really tall rider before I made one.

Five years prior, when he was a Denver Nugget, we had built a titanium gravel bike with 700C wheels for him that said “Bosnian Beast” on the down tube in place of our logo. The wheels looked undersized on that bike, whereas the 32” wheels made his e-bike look like a normally-proportioned bike. Without anything else in the photo for scale, you wouldn’t know it’s a giant e-bike.

Here’s Nurkić’s 32er e-bike (and alongside a 700C bike for a 6’9” guy in one photo for relative scale—note the more standard head tube length on the 32er). We’re now on Gen. 5 Bosch motors on our e-bikes, so this motor and battery are a bit dated:

Riding that 32er e-bike of Nurkić’s was a revelation to me. With the motor, the heavy Nimbus rims and tires were a non-issue when starting up, and boy, did it feel like nothing could knock me over when I got up to speed! Smooth fast, and all of that rotating mass made it super stable. It got me stoked to do more of them (for super tall people).

The Nimbus tires would certainly be shown to be slow-rolling in any lab test of rolling resistance, just from their construction methods. If you get one in your hand you’d see why. They have thick rubber that is certainly made of no special fast-rolling compound, very low thread count, and poor molding making them hard to install straight. So I never saw bikes with Nimbus 32” tires and rims to be anything you could compete on.

Me:

Did you or Zinn Cycles invent the 32” wheel or was it a size others were already using?

Lennard:

No, I didn’t invent them! It could have been unicycle.com. That’s where we got the Nimbus rims and tires from that we used exclusively on 32ers until recently when we could get lighter rims and tires from other sources. They are super heavy because these guys jump off big rocks and loading docks on unicycles with no suspension and need a lot of strength to land on one wheel that way!

Me:

For example, I know unicyclers ride 36” wheels.

Lennard:

Yes, also using Nimbus rims and tires, but in 36”, also from unicycle.com. 

The first 36er I ever made was a steel one for a tall artist from Tempe, AZ to take to Burning Man. He wanted it unpainted so it would rust and blend in there.

Me:

Wow, I had no idea that you had made a bicycle with 36” wheels too! I bet that was a hit at Burning Man.

Back to 32s, who do you recommend 32” wheel bikes to/for?

Lennard:

Riders over 6’9”.

Me:

How do 32” inch wheels “change the game?”

Lennard:

I claim them as game-changers for very tall riders for a number of reasons that I’ve mentioned above and will further detail below. 

I have not ever claimed that they “change the game” for anybody else. 

For tall riders, proportionately longer cranks make the proportionately higher gearing created by the tall wheels a non-issue, because cadence naturally goes down as crank length increases. For anybody else, low enough gearing can be an issue, because component companies have not (yet?) increased cassette sizes and/or decreased chainring sizes on stock offerings in response to the advent of 32ers.

Me:

Are they faster, better handling and smoother as proponents claim?

Lennard:

Faster?—hmmm. Certainly not uphill due to weight, and wind resistance would be an issue at high speed. 

I would think that in a well-controlled CRR lab test that they would be faster rolling in an apples-to-apples comparison with 700C, 650B, and 26”. Jan Heine didn’t mention (and could be why the lower CRR he quoted from Escape is on pavement) that increased diameter results in a lower approach angle of the tire relative to the road, resulting in a longer contact patch and less work done by the tire casing and less loss due to hysteresis (dissipating the rider’s energy as heat).

It’s simple physics, and anybody rolling loaded wheelbarrows around knows how much difference bigger wheels make. 

https://en.wikipedia.org/wiki/Rolling_resistance

Better handling? Well, stability is greatly enhanced. Existing carbon and suspension forks don’t have enough rake to make them nimble at speed.

Smoother? Yes. Absolutely. Just as we used to say that a 29” wheel won’t fall into a 26” hole, a 32” wheel won’t fall into a 29” hole” or a 26” hole!

Me:

What are the limitations of 32” wheels?: does a rider have to be a certain height, a certain leg length or can 32” wheels bikes be built to all size riders?

Lennard:

Absolutely the rider has to be tall or at least have a long upper body or favor a very long reach from saddle to bar or toe overlap of the front wheel will be an issue. So can swinging the leg over the rear tire be for a short-legged person. 

To correct for toe overlap, due to constraint on fork rake mentioned above, the builder’s only option for a short-reach bike is to reduce the head angle, which, combined with the low fork rake and high wheel radius would result in enormous fork trail and cumbersome handling.

Me:

How are your Zinn bikes designed to optimize the performance of the oversized wheels?

Lennard:

A picture is worth a thousand words.

Details for you to notice: super long top tube; as much fork rake as we can find in a carbon fork; a long crank with correspondingly high BB; generally tall bike so it is as proportional overall as, say, a 58cm bike with 700C wheels.

Me:

I ride 57 or 58cm road/gravel bikes – pretty average size. Are riders like me going to feel an improvement like with 29” wheels?

Lennard:

I don’t see why you or they would, no.

Me:

I think that’s the question most people will have if the size goes mainstream. 

Lennard:

Yup.

Me:

As a wheel builder I’m curious: did you have to have DT or Sapim etc. custom make extra long spokes for the new size?

Lennard:

No. We cut and thread our own spokes.

Me:

And what cross pattern are you using – 2X, 3X?

Lennard:

3X

Me:

Any issues with lateral flex on the bigger hoops? 

Lennard:

We do Boost in the front (110mm hub spacing) and Super Boost in the rear (157mm hub spacing). With that, we have not had lateral flex issues, and we are selling these to very big and heavy people. 

We made a Ti hardtail 32er last summer for Stacey King, who is 6’11” and weighs more than two average size men and he loves his bike. We made him a 700C Ti road bike 15 years ago (after another Chicago Bulls center of the same era, Bill Cartwright, got one from us). Here’s that bike (when he was lighter and 15 years younger), and you can see that those 700C wheels look tiny on it.

He sent me a photo of him with his 32er hardtail a few months ago, but I can’t find it. Nick Wigston may have it.

Me:

Are companies already providing gearing suited to 32” wheels, larger cassettes, smaller rings?

Lennard:

Already answered above. (No, not that I have seen.)

Me:

How are Zinn gbikes set up gearing-wise, for example on a common gravel bike 32” wheel bike?

Lennard:

Standard gearing, longer cranks. 

Usually standard SRAM XPLR 1X group with 13s 10-46T cassette. Chainring of 40T to 46T, depending on rider preference. Lower cadence means that standard gearing works out fine.

Me:

What’s your most popular (best-selling) Zinn 32er gravel bike model? (I’ll share a photo and link). 

The Clydesdale BFG.

https://www.zinn.bike/bikes/clydesdale-bicycles/big-wheel-bikes/32er-gravel-bikes

Our best-selling 32er e-bike is the eBFG.

https://www.zinn.bike/bikes/clydesdale-bicycles/e-bikes/32-inch-wheel-e-bikes

Me:

Do the 32” wheels increase the cost of that bike versus a 29er?

Lennard:

Yes. 

And obviously, tire and rim choices are reduced. 

We had a 32er MTB stolen last September in a smash-and-grab breaking and entry at our shop (among 7 bikes stolen that night). It was built for a 7-footer and had carbon 32” Nextie-rim wheels with Super Boost/Boost hubs. Even if they parted it out, I have no idea what they would do to get rid of that bike or those wheels.

Me:

Are there tires & tubes in enough variation for gravel/road or are there only a few manufacturers and models right now?

Lennard:

Very limited. Essentially only MTB and unicycle tires right now.

Me:

If so, do you see the selection improving soon?

Lennard:

In the current bike industry desperation, yes.

Me:

How light can a bike with 32” wheels be?

Lennard:

Not light. Nick Wigston here at Zinn can probably tell you the weights of some 32er bikes we’ve done. [Editor’s note: I did not check with Nick as it occurred to me that someone sized to fit these bikes probably isn’t that concerned about weight.]

Lennard:

Weight has come down a lot since the Maxxis Aspen tires came out and the Nextie carbon rims. 

We have made Ti 32ers in road, gravel, and hardtail MTB, and we make aluminum full-suspension 32ers

Me:

But, is there a significant weight penalty?

Lennard:

I’d call it significant, yes.

Me:

Do you think we will see road bikes with 32” wheels and if so, how soon?

Lennard:

Yes. We already make them and have done so for 6 years! (Road/gravel, since currently there are no tires under 2”.)

As for the rest of the industry: no idea.

Me:

It’s been great talking with you again Lennard and I can’t thank you enough for sharing your experience and knowledge.

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Jim Langley is RBR’s Technical Editor. A pro mechanic & cycling writer for more than 40 years, he’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Tune in to Jim’s popular YouTube channel for wheel building & bike repair how-to’s. Jim’s also known for his cycling streak that ended in February 2022 with a total of 10,269 consecutive daily rides (28 years, 1 month and 11 days of never missing a ride). Click to read Jim’s full bio.