We Chat to Andrew Carman About Everything Scrub Wheels.

What does it take to get a wheel brand off the ground these days? Andrew Carman from Scrub Wheels has done just that.

There’s plenty of options out there for wheels these days, so where do you start when you want to get a wheel brand up and running? Scrub Wheels are a one-man band doing hand-built carbon wheels out of Northumberland, we caught up with Andrew Carman to find out more.

What was the impetus for starting a wheel brand?

I’ve always loved riding bikes. My first race was when I was 10 and have basically been obsessed ever since. Through school and university I always held on to a notion that I would one day end up in a job I loved where I got to do cool stuff with bikes. After a few years it slowly started to dawn on me that the direction I was going didn’t get me to where I wanted to be. If this is what I wanted, I had to actively pursue it, it was not just going to “happen”.

My first bike job was in a workshop when I was at school. I have always loved building wheels. Taking a handful of parts which have little inherent strength and turning them into something that can take massive loads and abuse is something that I find pretty satisfying to say the least. You can’t rush a build. You risk making a mistake or compromising quality. You have to be in the right frame of mind and basically shut everything else out, it’s relaxing in a way. Starting a wheel building business tied together a lot of those threads and seemed the obvious thing to do.

Once you’d decided to build your own wheels, what happened next?

The first step was to identify a manufacturer who I could work with who could supply the rims to the specification I was after. Following loads of research I started to hear good things about one company in particular. Their customer service is amazing and working with them to get the product right has been a refreshingly straight forward experience. There were a lot of unknowns with the first order however everything went very smoothly.

How many people are involved in that process and what do they do?

My pal Paul is responsible for the branding and graphic design.

Web design, admin, buying, marketing, stock control, packing, dispatching, IT, accounts, making the tea, oh and building wheels that’s all me. It’s pretty much a one man show at the moment.

What did you know you wanted to do with these wheels?

I knew I wanted to build a carbon Enduro wheelset that is as accessible to as many people as possible but without sacrificing any of the quality or the reliability associated with more expensive options. To achieve this hand built is the only way to go. It not only gives riders peace of mind it means I can be 100% happy that a wheelset is right before it goes out of the door.

How difficult is it to nail down spoke number, offset and internal rim width?

32 spokes per wheel is a great place to start when building MTB wheels. You can easily achieve a really good balance of stiffness, strength and weight.

With the Carbon 30 I wanted a wheelset that above all would be tough and reliable. There are potential weight savings to be had by dropping to a 28 hole rim though I feel that these savings are simply not worth it given their intended use. In my range I also have an XC focused wheelset which has a greater importance on low weight so here I use 28 spokes per wheel and lighter spokes. It’s really driven by the application.

I chose to go with a symmetrical rim profile for the Carbon 30 as I’m not yet sold on the advantages of an offset (asymmetrical) rim. In theory Asymmetrical rims allow for similar average spoke tensions between both sides of the wheel.

You still need to ensure that the spokes on the same side of the wheel remain as similar as possible. In this respect they are the same as a conventional rim. Keeping this relative variation low between same sided spokes has a far greater effect on strength and reliability and is the sign of a well-built wheel, be is symmetrical or otherwise.

The “30” in the “Carbon 30” refers to the rim’s internal width. I decided on 30mm as they work nicely with tyres anywhere between 2.35” and 2.6” which covers the vast majority of modern trail / enduro mtb tyres.

Do industry trends heavily affect design decisions?

As the industry introduces new technology and leaves others behind, some will naturally stick around and become the “standard”, riders will expect these bases to be covered. So in that respect to give customers what they want I have to keep an eye on where the industry is at and where it might go next. In many ways though, the basic arrangement of the spoked cycle wheel has changed very little in a long time, like decades. There have been many attempts over the years to try and improve various aspects of the design. Carbon Fibre as a rim material is perhaps the biggest change to have seen broad acceptance across most disciplines of cycling.

How did you go about the pawl setup?

The freehubs I use have a total of 6 pawls in each. The 6 pawls are arranged in two groups of 3 and are slightly offset from each other. Each group engages in turn keeping the angle of engagement down. There are 54 points of engagement giving an overall engagement angle of around 6.5 degrees.

What made you go with a carbon rim?

Carbon allows great flexibility when deciding on the ride characteristics of a wheel. A lot of people assume that carbon means light weight but that’s not really the whole story. Carbon makes it easy to precisely control the shape of the rim profile and it’s inherent characteristics.

The Carbon 30 uses a different layup front and rear. The rear receives extra material resulting in a stiffer and stronger wheel whereas the front benefits from greater compliance.

Strength, stiffness and weight can all be balanced which above all gives great ride characteristics.

What’s the process of weighing up using another brand hub, rebadging an existing hub, or designing your own?

Choosing a hub brand and supplier was actually pretty straight forward. I’d used Bitex hubs on loads of previous builds and always been really impressed with the quality. They have a history which dates back nearly 100 years so must be doing something right. The huge number of axle and freehub options available make it really easy to switch between setups which is great for the customer but also from a stock perspective.

TLD A3 Helmet

Bitex were one of the first manufactures to license the Shimano Micro Spline freehub. Its great to be able to offer the flexibility to choose from any of the 3 freehub types and even allows existing customers to keep up to date with new standards.

The logo etching is done by a local company who can react quickly and is happy to work in relatively small batches which is just what I need.

In future I would love to bring hub design and manufacture in house. I’ve got some ideas for features which I think would be really cool and worth investigating though for now at least I’m really happy with what I have.

Does it take long to get a working prototype in-hand?

Manufacture of the rims is actually a surprisingly quick process. There is then some time waiting while they transit to the UK and then they sit in a warehouse waiting to clear customs. From the initial order to having the first pairs ready to ride would have been about 2 months.

How many prototypes did you make before settling on what would be the production model?

There have been so many minor tweaks it’s pretty hard to keep count! I probably got through 5 or 6 complete wheelsets before finally being happy that everything was right.

Beyond prototypes, what form did your testing take?

Lots of miles, in as varied terrain and weather conditions as possible! There is no substitute for real world testing. I take a lot of measurements too. Frequent spoke tension readings, and measurements really help me to understand exactly what is happening to a wheelset.

How important are athletes to testing new product?

Absolutely key. I’m lucky to have people who I trust to provide me with honest feedback. The importance of having riders who have the ability to push the wheels to the maximum and feedback to me with honest clear information cannot be overstated.

Did you have a Eureka moment when you knew you’d got it right?

The initial prototypes used waterproof vinyl sticker decals. To achieve the design they had to be quite complex shapes. This made them awkward to apply and prone to peeling.

I decided that the way forward was to have the decals applied “in mold”. They are now integral to the rim finish so much harder wearing and they give the whole product a real premium finish.

When the first batch in this style arrived and I unboxed them, that was a pretty special.

Any disasters other than COVID?

Sure there have been set backs but nothing that I would call a disaster. It’s fair to say that I’ve learned a lot over the last few years.

The main issue that I’m currently dealing with is the effect of new regulations on imports to the UK.

Getting stock shipped over here has become more complicated and more expensive. Some of my suppliers will no longer ship to the UK so I’ve had to find alternative sources which ultimately adds cost.

I think there is a lot of uncertainty at the moment which I am hopeful will settle down soon.

Favourite moments?

Seeing my wheels out on the trails never gets old.

People to thank?

Anyone who has stopped on the trails to chat about wheels. Anyone who has helped in the testing and development over the years. Everyone who has trusted a small brand with their hard-earned money, it does mean a lot.

You can check out everything to do with Scrub Wheels on their website here.

Read our Wise Words interview with Andrew Carman here.

Read Pete’s review of the Scrub Wheels Carbon 30 wheelset here.