This post is prompted by a phone call today asking about do deep rimmed wheels make a difference. Well they do in short.

Those more at ease with the physics of this will notice what I am presenting here is a basic model but it illustrates what going on.

One common misunderstanding is that aero gain are only important at higher speeds. Not true. Power required to overcome air resistance is directly proportional to the drag coefficient.  Often people relate power to the riders velocity but since this the variable here the constant of proportionality is the drag coefficient multiplied by frontal area, CdA for short. 

So a 5% reduction in CdA results in a 5% reduction in power used at any speed. Since a slower cyclist spends more time on a course that leads to the slower cyclist saving more time in tt with aero wheels that say Alex Dowset would if one could persuade him to the Lavenham 10 on Mavic Askiums compared to the BORG50C for example. That's not the same things as saying aero wheels benefit slower riders more than faster riders as that's not true. If the same time difference were expressed in terms of a % then the faster riders see more of a % percentage benefit than the slower rider. 

So air resistance can be 

Power to overcome air resistance P(ar) = 0.5 × CdA x rho x v^3

Wheels change the CdA of the rider and bike and through that affect the riders velocity.

Rho is air density which is 1.2 kgm^-3 

for your average cyclist moving at 18 mph on mavic askiums then a set of BORG50C wheels will add 0.5 to 1kph to your speed roughly.   This may or may not be significant to you. If it isnt and for most people it isnt then your buying based on looks. Nothing wrong with that. 

 I am going to refrain from predicting time saved for particular course as such calculations are not meaningful.

This is a guide for home bike fitting. It's a service that I no longer provide due tine constraints. This guide works for all road bikes, MTB's e.t.c you know bicycles. This guide avoids the usual methods like kops which if used in isolation end up confusing the fit rather than enhancing it. Bike fitting is a process and you cannot start in the middle then to the begining and then move to the end. Follow the guide as I lay it out and it works. You may also find you dont need that new saddle after all. 

Bike fitting is pretty straightforward. All bike fitting start it must start with the saddle

Step 1 now level that saddle off with a spirit level. Some saddle have a shape where a spirit level is useless you can either change your saddle here or use your eye. Tilted down a couple of degrees wont hurt (old shimano seatpost only allowed your seat to be nose down slightly) but you might slide forward a bit. Nose tilted up is never desirable.

Step 2.
Now set your saddle height. This is measured from centre of bb axle to the top of the saddle. Once this is determined this is fixed height for all your bikes. The saddle height is the single most important thing to get right which is why it has to be done first. The lemond method takes your inseam measurement (taken with a book jammed into your crochet and a tape then dropped to the floor) and multiply it by 0.883. This is your saddle height but it only a start. It may have to go up or down a bit. The weakness here is crank length. It takes no account of crank length with 20+ bikes with cranks from 165mm to 177.5mm my saddle height has to vary a bit by a couple of mm from bike to bike. For me its 795mm. Correct saddle sort many knee issues out.

If your hips rock alot or you have dip your foot at the bottom of the pedal stroke then your probably got your saddle too high. Let your legs dangle when on the saddle. The angle your lower leg make to your upper is not far off the how your leg should look at the bottom of the pedal stroke. You can do this bio mechanically without measuring anything. I know the how your leg should look by eye. You may not but you can set your saddle height by raising it till your hips start to rock when pedalling. If there is more than 2cm of movement left hip to right hip then your saddle is too high. That's not an exact measurement but your hips should not be rocking. Your foot is another tell tale sign. When pedalling the tow of your foot should be pointing up a bit, like your scraping shit of your shoe. Whe your saddle gets too high you toe no longer does this so stop raising your saddle. Between these three observations the saddle can be set. Once it is set correctly, measure it.

http://veloptimum.net/Velop/documents/1-choisir/RBR15juil10.htm

Step three. Sit on the bike and pedal. Do this for a minute of two until your settled. Note how far back your bum is. Your bum should be at the back of the saddle. Adjust saddle for and aft till your bum is at the back of the saddle when pedalling normally.

Now that's the saddle set. Dont alter it. This is fixed unless your leg length changes. Most saddle comfort issues are addressed by proper positioning. Saddle choice is often affected by position and clothes worn. Harder saddles work well for long rides with padded shorts. Soft saddles are fine in civies and shorter journies. The more upright your position the wider the saddle can be. The flatter you are the narrower the saddle needs to be. If proper position does not help you your saddle has to be changed.

Now to the front of the bike. When one is sitting on a bike you should really feel like your in it. This means something specific in terms of position. Your back should be straight
Not ruler straight as backs are not like that but you should not be hunched or have an excessive curve in the upper half of your back. You should feel relaxed. Your arms should be slightly cocked on the tops, hoods and drops. Your arms should also be perpendicular to your torso. If that arm to torso angle is greater than 90 dgress your probably over stretched and the shape of your back will show it. Your shoulders should not be pushing back out of your back. This leads to bunching. You end up cranking your neck then. Essentially imagine your standing then bend over,that how your back should look. Your neck then sorts its self out. To achieve this position you have stem length, rise and bar reach/drop to sort alter.

You can take any position from upright to flat and makes an arc because you arms in all cases are only slightly cocked I.e a relaxed out position. Even if you think your not flexible you dont have to have the bars higher than the saddle. That's for upright positions. Upright right positions are not more comfortable. They are used or should be for improved visibility. This is important in urban areas. Hense riding tt bikes in cities is not always wise. That old trek bike below is mine. I cant get within 15cm of my toes when trying to touch them yet I consider that position on the dirty old trek to be conservative. Lacquer is peeling but it works hand that all that matters really. It's also offers a comfortable position for 200+ mile rides. Again its comfortable well as a comfortable as a alumium bike is with 22mm tyres that is. With proper position you can adopt a range of positions on the arc your body shape allows. You can of course ride in a more upright position it's perfectly fine if it's on the arc of acceptability.

So step 4.

Adjust your bars so the drop ends are parallel to the ground. Tilted up a bit is acceptable. Exactly how they sit will depend on your shifter brake levers. shifter/brake lever position should lever a flat area for you hands with modern unit. The bar tops to the levers are essentially flat. When levers are pointing up to bring them closer that a sign that the bar reach or stem length is too long. This also has the effect of putting stress on the wrists as they are no longer in line with your forearms. Perhaps the steerer has been a cut too short, in other words parts should be changed. Old bikes with old brake levers dont give you this luxary. Your meant to sit in the drops and brake from the drops.

Select your bars so you can sit with your hands on the tops,hoods and drops and operate all the controls without you shoulders pushing back, arms straight but slightly cocked and you should feel relaxed. If your too flat you'll feel it. I get pain around my hip and crotch if I am too flat.

Stem length is picked to complement the bars. Stem angle is the last main thing. Stems come in different angles. Commonly road bikes have a negative angle stem so with commonly used head tube angles. They can be either way up and flipped they raise the bars but shorten the stem. 82 to 84 degrees angle is common. 0 degree stems are neutral. They are the same flipped. Stem with rise will pull the bars in as they lift them. So be careful your not creating undue bends in your arms. The higher the rise the shorter the stem is effectively.

You can also lift the stem up which was easier on old quill stems. Given the head tube angle lifting the stem up means pulling the bars back so stem length may have to alter.

Most of the problems start with position when the rider feels uncomfortable and starts altering the front end in a haphazard way often making matters worse.

That's the basics it can be done at home. The approach has to be methodical.

Of course it helps to be on a frame that is sized so you can make it fit.

Being a bit a of a tubeless tyres fan here are my thoughts. They dont cover all tyres as I have not tried them all. For context I am 86 kg and most of my tubeless tyre riding in winter on heavy bikes with panniers on the back. In summer I have a tubular tyre habit, as expensive as heroin - could it be the glue? I do use tubeless tyres in summer too. Clinchers are banished.

I'll start with IRC because I distrubute these. I am biased. I love these tyres.

IRC have 4 road tyres, 6 CX tyres and several MTB tyres. IRC tyres are not the lowest rolling resistance tyres out there. I dont care about that because they are hard wearing and grippy, oh so grippy in the wet. 

IRC Roadlite tubeless- this is IRC fastest road tyre. It is also the least grippy of the 4. That's a relative term as it's still grippy. Cut resistant and good training tyre that you can race on. On Borg rims the 25mm tyre is 27.5km wide and 24mm tall. They hold air well being a butler lined tyre.oh they are comfortable too. I did PBP on these.

IRC Formula Pro X Guard - my favourite road tubeless tyre full stop. Its  grippy in ways other tyres want to be and it hard wearing too. The puncture protection belt keep the P fairy at bay most of the time. 6000km from the rear tyre on my pannier laden commutor is normal. No other tyre last me as long. On borg rims these tyres size at the size they should be. Comfort is quite good on these tyres. Enough for 200 mile rides. It's a lined tyre as well so holds air pretty well.

IRC Formula Pro RBCC - the wet grip on these is insane. Plush dugast tubulars or Vittoria Pave tubulars are as grippy.this is high praise. Grip is this tyres party trick. As durable as the X-Guard but not as puncture resistant. Comfort on these is fine and I done many 200+mile rides on these tyres. It's a lined tyre as well so holds air pretty well.

IRC Formula Pro Light - well it lighter than the other tyres in the range. It's meant to have lower rolling resistance but it's not a tyre that meets my needs. It has thinner sidewalls but this tyre is still more hard wearing and its sidewalls are thicker than many others. It's a lined tyre as well so holds air pretty well.

IRC Serac tyres. They come in Sand, CX or Mud version. There are X-Guard versions of all three 32mm only. These are CX tyres really and I don't do CX (horrible sport, tried it once and it was hard) but the sand tyre is a good narrow gravel tyre. 

IRC Boken and Boken + I dont own a gravel bike. Gravel to me is old fashioned XC riding so I do that instead. However I know many gravel riders that love these tyres for there grip. There are lighter and faster gravel tyres but for grip well this is your tyre. Grip = fun and it keeps you upright. 

IRC Mythos, Serac XC and Stingo since enduro and down hill scare me I have not tried IRC tyres for these disciplines but I do use there XC tyres. Like the other tyres there are lower rolling resistance tyres but once again IRC's party trick is longevity and grip. The mythos is my summer dry tyre and the Serac XC and Stingo are my winter tyres unless I am using Conti tyres.

Continental well they make the Competition tubular which is the best tyre in there range. The grip is insane. I love these tyres however Continental make some really good tubeless tyres now.

GP5000TL - I call this a  TT tyre because its quick. In fact its possibly the fastest relaible tyre out there. During my winter test on my commutor the rear lasted 2500km before it wore out. Longevity is not there thing. Grip is pretty good and they have a damped feeling. You want these because they are quick and reasonably reliable. That's it. Some people think they are tight so use an IRC tubeless tyre lever. You wont break one of these and these lever help you lever these tyres on. I have no trou le fitting them but then again I have no trouble fitting Conti tubs either. 

Race King and Cross King - I really like these tyres. Faster than the IRC's but conti tyres are thinner so punctures are more likely. Still for a fast decently grippy tyre there is nothing else I go for. 

Conti gravel tyres- no idea I still think gravel and XC are same thing. 

Hutchinson- back in 2006 the French and Shimano teamed up and established a tubeless standard so you think Huthinson would know what they are doing and they do.  Hutchinson make tyres for Pirelli, Zipp and Mavic.

Hutchinson Fusion 5 Performance- pretty quick and reasonably puncture resistant tyre. They wear out ( rear after 3000km) fairly quickly but they are one of the cheap road tubeless tyres so this can be forgiven. Grip is pretty good as well.the fit is pretty easy.

Hutchinson Fusion 5 Endurance - pretty quick for a winter tyre and decently reliable. I am still wearing my set out but it look like after 1500km they are half to a third there way through there life. Comfort is there down fall but that a relative term. They are way better than a Conti Gatorskin in any size. The fit is pretty easy.

Mavic Yskion Pro UST.the compound is the same as the Hutchinson tyre but the for is meant to be better. They however are just as easy to fit as the Hutchinson tyres. They hold air well, offer good wet grip and are fairly quick tyres. Puncture resistance is fair and they wore out (rear) after 3300km.I like them and would use again. 

Goodyear Eagle - tubeless tyres should really comfortable and most are. This is the only tyre that transmitted road buzz and a noticeable ammount. The bike buzzed. Grip was o.k and they reliable enough but after 800km they delaminated and the importer blamed it on my sealant choice. Its not the sealant. Oddly enough they are not for sale here. Unless the importer backs up retailers I cant be bothered selling them.sowhy sell a  buzzy tyre. 

Schwalbe - i have tried to like this brand but i cant stand any of there tyres. They hold air fairly well for a tubeless ready tyre and there fit is secure. Schwalbe do understand the ERTRO standards.

One tubeless - this older model punctured quite a bit but grip is its main problem. In the wet they scared me. Cornering on these in the wet is something best done slowly. They are quick though in a staright line, in  the dry. 

Pro One - I once tried selling these and customer after customer told me how shit they were and they are going back to tubes. I tried them and they are shit. Oddly enough I dont sell them now. The wet grip is O.K but nothing special. They are quick enough while they are holding air. The slowest tyre is one that puctures. One ride home(15 miles) i got 6 punctures on an unworn tyre. Nothing is slower than a flat.

Yes that's 6 flats in 15 miles, thats 6 plugs and I am sure there were more holes. They leaked from places I couldn't even see. If your light and lucky you might get away with using them but the conti GP5000TL is a better fast tyre. 

Schwalbe Rocket Ron and Racing Ralph. I cant understand what the fuss is about. Yes they are really quick but I go wide in the bends with them. Give me a Conti or IRC XC tyre anyday. 

Schwalbe Marathon supreme - I don't have a road bike that can take them. Given Schwalbe's compound choice I am not likely to like them. 

Vittoria Corsa Control G2.0TLR - grippy and comfortable but best used with inner tubes

Oh wait they do a tubed version which is cheaper so buy that instead. So what wrong, well they are tubeless ready and while that not a problem normally in this case it is. My pair were porous. Sealant never fixed this. The sealant dried out after a week or two meaning punctures never sealed. They punctured. After 3300km I got fed up and binned them. I'd use them again in tubular form though. In er tubes for me belong in  sew up tyres only. 

Vittoria Rubino Pro G2.0 TLR - I am only about 1000km into testing these and so far they are great. There are more comfortable tyres but in 28m. Form they are comfortable enough. There are tyres with better wet grip but these are grippy enough. There are faster tyres but you dont get the Rubino for speed. They are fairly low cost for a tubeless tyre, pretty reliable so far and they look as if they will do high miles. On wide rim the 28mm tyres only co.es up at 26.8mm which is why they probably loose on the comfort front a bit. These are pretty good tyres so far. They hold air well too. 

Vittoria's other road tubeless tyres are best off with inner tubes in. 

Vittoria do make some good MTB tyres however the ones I have used were branded Geax. Not tried there newer models. 

Tyres in stock for testing are Verdestien Fortezza and Challange Pris Roubaix. 

 I might have forgot a few on the way. Oh here's one Dugast ORI tubeless tubular MTB tyres. Hopeless. I love dugast road tubulars but there MTB tyres have never lasted well. The ORI tyres are puncture prone in the extreme and sealant never seemed to help.