For the last 10 months, I have been testing bikes and different bike parts by measuring their impact on comfort in terms of lowering the perceived riding vibrations. Below you will find a short summary of my findings and questions that I still need to find the answer to…
Does supple tire really make a supple ride?
In a short answer: Yes!
For years I have been reading reports stating that this tire is much more supple than that tire and it improves the overall comfort dramatically. So naturally I wanted to find out if this is indeed true. I compared a not so supple Panaracer GravelKing SK 700x43c tire with much more supple Soma Cazadero 700x42c tire. The results are very clear: both in terms of slow but very bumpy forest ride and fast gravel grinding the more supple Cazadero tire provided up to 13,4% less vibration than a GravelKings. The best results were on the forest route where the tire could really show its flexing abilities. On gravel, the improvement was much more modest but still up to 6%.
Does a wider tire bring much more comfort?
In general yes, but…
First, you have to realize that the bigger the tire the less air pressure you have to use to make it comfortable. This is based on Laplace’s law which says that the tire casing tension = internal pressure x tire’s radius. This means that to get the same tire tension you have to lower the tire air pressure when you go for a wider tire. The explanation is very simple – the bigger the tire, the more air will be in it at the same air tire pressure and thus the casing tension will be bigger. You can verify this experimentally. Just get two tires with different width and inflate them to something like 30 psi air pressure. Then try to squeeze the tires. You will quickly find out that the wider the tire the more force you have to use to make the same dent. The Laplace’s law makes the comparison between different sized tires run at the same air pressure simply pointless.
Then there is the tire suppleness. If you already have a very supple tire then going wider will not necessarily make a big difference. My latest 650b vs 700c tire comparison was based on Soma Cazadero tire and I found out that, yes, the bigger the tire the more comfort it can provide but the comfort increase is not that substantial and to be honest, there is no point in going wider than 50 mm tire (either 700c or 650b) because then you would have to use an air pressure below 20 psi to make it beneficial and this can have a bad impact on the handling of the bike (the tire will not behave optimally, especially in tight corners). So in general, I would recommend using a supple 700c 42mm tire run at 25 PSI to get the best of both worlds (good rolling characteristics of 700c wheel and a nice, supple ride).
Should we all jump on the 650b bandwagon?
In a short answer: not really.
I have bought a 650b set of wheels and mounted on them a Panaracer GravelKing SK 650bx48 tires. My initial observations (based on my benchmark bike equipped with suspension stem and flexing seatpost) were that a smaller wheel but a more voluminous tire (compared to 700x43c) run at 30 psi does not change the comfort of the bike dramatically in any way. Then I made another test, this time based on Soma Cazadero tire that was also not that favorable towards 650b wheels and tires. Moreover, I feel that a bigger wheel is rolling better over bumps (thanks to a bigger radius) and I did not like the quicker handling that 650b wheels introduced to my benchmark bike. This means that if your bike has already quick-handling, then going from something like 700c 42 mm to 650b 50 mm will probably result in nervous, too quick handling. But if you want to make your bike quicker, than you should consider switching to 650b wheels. You just have to get used to a slightly weird feeling that you are riding on a smaller bike, or should I say, a small tank that will ride on anything…
Should we all lower our tire air pressure?
In a short answer: YES!
To be honest I am constantly amazed by people not wanting to try and experiment with their tire air pressure. Yes, maybe (but this is not a certain thing) you will be a tad slower, but riding a tire at something like 25 psi (which in my opinion is the best compromise between safe riding characteristics and the comfort on 700c 40ish tire) can dramatically improve your overall comfort. It is even enough to lower air pressure from 40 psi to 30 psi to see more than 32% comfort improvement (fewer vibrations) in the front of the bike and 17% in the rear. This was achieved on my benchmark bike with Panaracer GravelKing SK 43c tire.
Does a tubeless setup improve comfort?
In a short answer: Probably not, but I saw some data saying that on a fast gravel route there could be a small difference.
When I was testing different tires on a Canyon Grail bike I compared the tubed vs tubeless results on the stock Schwalbe G-One Bite tires and it looks like, especially on a fast gravel route (a lot of high-frequency vibrations) you can feel some benefits of having tubeless tires (but it is only 3% improvement over tires with inner tubes). This I think is an effect of an inner tire bouncing within the tire and thus creating more vibrations (but I would need to do much more testing to be sure). From my perspective, tubeless tires improve the overall riding comfort because you don’t have to worry that much about flats anymore and this is quite important, at least, for me.
Can you expect a comfort difference between different forks?
In a short answer: Yes, but a very slim one.
When I was testing a GT Grade Carbon bike with its flip-chip fork I had an opportunity to measure a possible comfort difference in terms of different fork offset. To my surprise, there was a small but measurable change between the forward and backward position of the wheel. If you think of it (and when you look at a fork of my benchmark bike – Jamis Renegade which uses an ECO Compliance fork) there is something beneficial in putting wheel slightly back. From my understanding when fork and wheel are in the same line the hits go straight to the handlebar but when the wheel is moved back than the fork itself bends more reducing slightly the impact force before it reaches the handlebar. If you look and a Lauf Grit fork you will quickly notice that apart from suspension itself, the wheel is also moved far back and thus promotes more compliance.
But offset is not the only thing that is important. Even more important is the carbon layup of the fork itself which was very clear when I tested Lauf Grit Sl fork, Open U-Turn GravelPlus fork, Argong’s 18 Dark Matter fork and my fork from Jamis Renegade Exploit bike. Fork from Open is a simple constriction without any gimmicks (like a bend in Argon’s 18 fork) but still, it was performing very well, even beating Lauf Grit SL on a fast gravel route (it was absorbing more vibrations). So yes, the fork can make a difference and you don’t have to buy a very unique and expensive Lauf Grit Sl fork to experience that…
Should we put more attention to the wheels itself?
In a short answer: Not really! Especially if you are using very supple tires…
I have bought a pair of Spinergy wheels with its unique fiber PBO spokes which should improve comfort (because they behave like small springs within the wheel). And yes, you can feel the difference, but only on a very bumpy road (not with high-frequency gravel chatter) and it is a very small difference (5-6%). Honestly, just for this, I would not recommend buying that wheelset but I also managed to lower the overall weight of the bike (because Spinergy GX wheels are very light) and this, combined with very light Rene Herse Barlow Pass tires changed the bike substantially. Now it is not only slightly more comfortable but also much quicker. And I like that.
Should we buy a flexing/vibration reducing (carbon) handlebar?
In a short answer: Not really.
My tests showed only a very small difference between normal aluminum, unique aluminum (Spank with Vibrocore vibration reducing foam), and carbon handlebars. Yes, subjectively you can feel that carbon is flexing much more than aluminum (when on tops, and especially on drops) but this not translates in huge comfort improvements in terms of vibration reducing. The difference is there, but I would think twice before buying a carbon handlebar just for the comfort improvement, especially on a gravel bike that is prone to crashes and hits (and we know that carbon does not like that very much).
Should we put more attention to the handlebar tape, shorts, and gloves?
In a short answer: I don’t know yet.
This is the aspect of improving riding comfort that I still need to properly evaluate. But I am not in a big rush for it because from many different articles about bike compliance I have learned that the impact of handlebar tape, bike shorts, and gloves may be very hard to measure with my phone vibration app. For now, I can say that subjectively the ride was harsher when I was testing handlebars without a bar tape but the difference was much less than I thought it would be…
How much comfort can you gain from the saddle?
In a short answer: A lot, but not necessarily in terms of vibrations dampening.
I have already tested different saddles and found out that yes, there is a difference in vibration-reducing properties between saddles. Especially when your frame and seatpost is rather stiff, but when you ride something like GT Grade bike or you are using a suspension seatpost, the more important thing will be overall riding comfort and choosing the saddle that will fit you best (this should be no surprise to any experienced rider). I have tried many different saddles and for a long time I was using Brooks C17 saddle but I switched to SQ Lab 612 Ergowave Active because Brooks was not cooperating well with my current suspension seastpost of choice (Redshift’s one). I can wholeheartedly recommend both of those saddles but again, a saddle is a very personal thing so try different ones yourself before you choose the one you really like.
How much comfort can we gain from a well-engineered frame?
In a short answer: a lot, but the difference decreases significantly when you start using proper supple, wide tires with low air pressure.
A good steel made frame works like a spring and can dampen the vibrations so effectively that even the newest and latest advances in carbon technology sometimes can’t compete. But solutions like flexing seatstays of the new GT Grade are also very effective. GT Grade carbon gives so much compliance that you simply do not need to add anything like a flexing seatpost or a big tire to stay seated and enjoy the comfortable ride no matter the surface. So yes, a frame matters but again, if you have properly supple tires and use something like suspension seatpost and suspension stem, the frame itself will have only a marginal role in the overall comfort improvement.
Should you use a flexing seatpost?
In a short answer: Yes! Unless you ride a new GT Grade Carbon ?
Suspension seatpost can dramatically improve the rear end comfort of your bike and solutions like Redshift’s suspension seatpost are hard to beat in that department. Although I still prefer the feeling of Ergon CF3 / Canyon VCLS 2.0 carbon seatpost, I currently use Redshift suspension on a daily basis and I think I will not change it in the near future. It is that good…
Should you buy a suspension stem?
In a short answer: Yes! No question about it!
From my testing experience and all the knowledge, I have gathered I can honestly say that buying a suspension stem like Redshift Shockstop stem is a single best thing (apart from simply lowering your tire air pressure) that you can do to improve your front end comfort. Yes, Future Shock from Specialized is, in my opinion, better in reducing vibrations but you have to buy the whole bike to get it and Redshift suspension stem will significantly improve the front end comfort of any bike out there. And for sure, I would recommend it even to those who are considering something like front suspension fork. Honestly, try the Redshift suspension stem first before you will invest a much bigger amount of money for things that you may not need at all…