Why fit Carbon Wheels?
“The 11 reasons to give your partner when justifying the purchase of carbon wheels”
By Colin Leeson
Owner TLR Race Wheels
They say that adding a set of Carbon wheels to your bike is the best way to make it look super sexy.
This is certainly true, but you might be surprised at the amount of other reasons why you would set yourself up with carbon wheels.
As owner of the TLR Race Wheel brand, I am constantly amazed to hear how people's performance improves after purchasing their new wheels (or renting them through our TLR Race Wheel Rental business). This excites me about the product we supply and the benefit we can provide for people competing in our sport.
I share with many of our customers the following "11 reasons why you need carbon wheels” to improve their bike performance.
It is said that up to 95% of riding effort is used to overcome wind resistance and the other 5% is actually used for efficient propulsion. The objective then is to make everything to do with cycling as streamlined as possible. This is why frames, components, wheels, helmets, seating position and even the type of material used for clothing are constantly evolving to gain precious advantages in the 95% part of riding.
The first three points are on aerodynamic advantage:
Deeper dish. Airflow around the wheel as it slices through the air is the first aerodynamic consideration. In a normal “standard” rim the airflow is quite turbulent as it wraps around the tyre then behind the rim into the spoke area. This turbulence is reduced on deeper dish wheels. To summarise quite a technical subject, the deeper the dish, the less turbulence at the back of the rim allowing them to slice through the air faster.
The shape of the wheel is also an area of improvement with the most current wheels using a “U” shaped rim whereas not long ago the “V” shape was thought to be fastest.
Rim width. Rim width looks at how smooth the sidewall of the tyre is compared to the side of the rim. Having a flat surface along this side again reduces air turbulence. Most wheel companies are now offering wheel widths between 23 and 28mms. Advice for which width to use varies on the intended purpose but for most customers we recommend a 23 or 25mm wide wheel with a 23mm wide tyre fitted to a 25mm wheel being preferred.
The combination of 23mm wheel and tyre has the tyre being slightly wider than the rim which gives very slight turbulence. The 25mm wheel and 23mm tyre means the tyre when fully inflated is slightly narrower than the wheel AND it is more solid on the road (later point)
Wind assistance. This is one of the newer realisations of carbon wheels. If you know anything about sailing (sail boats) you will probably know how they travel into the wind. They “tack” at an angle to the wind and the wind pushing across the sail propels the boat forwards. (This is different from when the boat is going WITH the wind direction where the big sail comes out and fills like a balloon and pushes the boat).
The exciting thing about deep dish carbon wheels is that if there is a wind coming from the front-side direction the wheel catches this wind and assists with forward momentum. This effect is most noticeable with a full disc wheel but is exhibited to some extent with a deep dished spoke rims.
Solidness on the road – tyre bulge
Imagine a 19mm wide rim with a 23mm tyre fitted to it. The tyre will “bulge” out each side of the rim by a couple of mm. We covered the aerodynamic problems with this bulge in point 2, now consider when riding this type of combination as the rider turns a corner the tyre will roll slightly from side to side on the rim with the cornering pressure.
Imagine the same tyre (23mm) fitted to a 23mm wheel. This time there is a smaller bulge and the tyre profile has a flatter curve. This reduces significantly the amount of side wise “roll” that the tyre has and also gives a wider flat surface for road contact.
The result is a much more “solid” feel to the ride.
People racing complex courses such as criterium racing and the typical triathlon draft legal courses benefit greatly by this.
Consider finally a 25mm wheel with a 23mm tyre: the result is an even flatter curve = more solid feel and better road contact. Our many Triathlete customers find this to be the best feeling combination.
Carbon wheels are light. Carbon is an amazingly strong product and is used in many applications to make products from bikes to cars and planes lighter and stronger. The benefit this gives to bike wheels is weight reduction. A typical pair of carbon wheels can weigh just over 1 Kg which can be 500 grams or more saving of weight compared with the standard aluminum wheels.
Rolling resistance (bearings / hubs). Most carbon wheels are supplied with superior bearings and hubs with allow the wheels to roll much better.
An interesting thing happens with deeper dish wheels. They can end up pushing the rider along the road. Sound too good to be true? This is what happens:
The full disc carbon wheels are the extreme example of this phenomenon where they build up a centrifugal force once spinning which propels them forward and keeps them spinning forward. (If you are mechanically minded this is just like a flywheel in a car engine.)
A disc wheel takes a little more effort to get “wound up” but once going it is significantly easier to maintain the speed thanks to what we refer to as this centrifugal momentum.
A couple of notes on discs:
Because they want to keep going forward, these types of wheels are harder to slow down too, so if the event you are entering has lots of turns and accelerations the disc is likely not the best choice.
In case anyone is asking, Disc wheels are used on the rear only. (the occasional exception being indoors velodrome racing) The reason is the effects of wind on the rear wheel are manageable whereas a disc front wheel would be extremely dangerous.
Disc wheels are an expensive investment and if you are a serious non-draft triathlete or TT rider with a couple of thousand dollars to spare a disc wheel will give you great results but for many the price is outside the budget.
The good news is deeper dish carbon wheels exhibit to a lesser extent these same characteristics. The 80mm R.80 and 88mm C88 rear wheel in the TLR TT Combos are a great mid-point option, allowing ease of braking at corners but still building nice momentum on the straight sections.
Power to road. As I pointed out, carbon is amazingly strong for its weight. This strength allows wheels to be stiffer in a sideways direction meaning less energy is lost by flex in the rim and more energy is transferred to the road. This results in more efficient riding.
Part of the reason for the wheel stiffness is the shorter spokes needed for a deep dish rim: deeper dish = shorter spokes = stiffer wheels
Flexibility in compression. This is another surprising thing about carbon wheels. While the wheels are stiffer in a sideways direction as described above they are more flexible in compression.
When first riding carbon wheels you might hit a bump on the road and it feels like you are riding on a partially deflated tyre. This is because the wheel has absorbed some of the impact of the bump.
The benefit of this for the triathlete is the ride becomes slightly more “relaxed” which leaves a little more in the tank for the run.
This point is a little harder to quantify but bear with me and you will agree.
There is something about how it affects you when you feel good. If you jump on the bike and it feels great then you usually find you do well on the day.
Why is this?
Clearly you can perform better because the bike is better, however it can also be argued that part of the improvement is you as an athlete doing better on the day simply because you felt good. It’s like the “having a good day” thing. You feel good on the day so you perform better.
So in summary fitting a set of carbon wheels always makes you feel better and the performance increase you experience is likely compounded by the fact that you feel good so perform better.
We mentioned number 11 at the start and it is that bikes look HOT with a set of carbon wheels fitted!!!
What do the eleven points really mean on race day?
It has been great hearing back from our customers from both wheel purchases and rentals as to how much the wheels have helped their races.
Consistent feedback from our triathlete customers suggests carbon wheels can give the following approximate improvements:
40 min improvement / PB’s over an Ironman triathlon 180k distance.
20 min over 70.3 (90k)
Up to 10 mins over Olympic distance events (40k).
Carbon wheels come in a wide range of makes and prices ranging from cheap imports for under $1000 through mid-range wheels up to high end brands like Zipp and ENVE and beyond for many thousands of dollars.
TLR Race Wheels
We set up the TLR brand aiming to provide a mid-range priced wheel which has great quality but suits the budget of the majority of age groupers / amateur athletes.
Our goal is to be the best wheel in our price range and feedback tells us we are achieving this goal.
We have two wheel series with a pair of the Aero wheels ranging between $1200 and $1600 and the up-specked Elite series wheels ranging between $1950 and $2200.
Note. With the decline of the $AUS over the last 12 months, our competitors have raised their prices by 30% or more. TLR Race Wheels have kept our prices stable for the last few years in an effort to grow our brand and gain some market share.
TLR also has a rental department where wheels are available for hire for those athletes wanting an improvement for a particular race but not ready or able to purchase wheels. (Australia only)
Find TLR Race Wheels at www.tlr.bike
I welcome any further questions you might have regarding carbon wheels and which ones suit your needs.