Reducing rolling mass and mismatched wheels

If you want to travel faster on level roads then you should look at aero wheels and read up on aero-dynamics. In this situation mass is not so important but aero is very important.
 
Rolling mass, mass in general, is important for hill climbing, especially if your gearing does not allow you to maintain reasonable cadence (80+). I think if your cadence is lower than 80, especially around 50 or 60, than rolling mass would be important.
 
Mass, rolling mass, and Aero are important for sprinting and time trials, especially rolling mass and aero,
 
Saving 250gms on rims and tyres is roughly equivalent to saving 500gms of bike weight. Low Rolling mass is important for fast acceleration but not for constant fast speeds on level roads (refer above).
 
Aero really only affects you from speeds of 25kph and higher, and especially 40+ (unless you are riding into a head wind, then its your speed + the headwind speed).
 
One thing I haven't mentioned is rolling resistance or tyre pressure. Every 20psi extra you pump into your tyres makes it easy to travel at higher speeds and ride your bike in general, but at the expense of a rougher ride.
 
I am sure I have missed alot out and hopefully I have condensed it all ok. I hope this is helpful [IMG]/img/vbsmilies/smilies/smile.gif[/IMG]
 
So, on the wheelset front, I believe that you are looking for a wheel with low friction bearing hub, aero spokes and rims, and low mass tyres that don't puncture easily [IMG]/img/vbsmilies/smilies/smile.gif[/IMG]

While it 's true that a reduction in rotating mass will let you accelerate faster, the difference isn't anything you'll be able to really notice as a recreational rider. If you could save a lb on your wheelset, that would be equivalent to saving nearly two lbs on your frame, but only when accelerating the bike. At a steady speed, weight of the wheels means the same as weight on the bike and rider.
 
For hill climbing, saving a lb of weight out of a total of say 200 lbs for bike and rider means you'll climb 0.5% faster. For a climb speed of 10mph, that's a whopping .05 mph....nothing you'll see on your bike computer. Of course, for a racer on a 20 min climb, saving 6 seconds just might make a difference in overall placement. If you're getting beaten by a few seconds on hill climbs, then a set of lightweight wheels could even the score. Of course, if you were interested in competitive road racing, you'd have a different bike.......
 
Bottom line, IMO it doesn't make sense to put light race wheels on a hybrid bike, particularly if you need to take it over small curbs, IMO, Mavic Askiums are nothing special. If you plan to ride alot, including some rough roads, trails and curbs, I'd recommend a custom-built set of 32 spokes wheels with Shimano or Campy hub from a good wheelbuilder. Many LBS have experienced wheelbuilders who can design and build a carefully-tensioned wheel to your needs.

Agree that eeking more performance out of your bike would best involve trading it for a performance bike. The biggest speed improvement you will see will come from putting your body into a more aerodynamic position on the bike, meaning a lower front end and drop handlebars. Until that is accomplished, shedding grams is virtually pointless.
 
I'm sure the 7.3 FX is a great bike, but its design is going to limit your ability to achieve higher performance and in trying to do so you will reduce its functionality as well (ie, inability to ride up and down curbs).

Quoted post said:

Originally Posted by KLabs [IMG]/img/forum/go_quote.gif[/IMG]
I
"One thing I haven't mentioned is rolling resistance or tyre pressure. Every 20psi extra you pump into your tyres makes it easy to travel at higher speeds and ride your bike in general, but at the expense of a rougher ride." quote.
 
So I can assume then that if I could put 240 psi in my tires they would be faster then running my current 100psi, assuming no blow outs of course?
 
You gave good information till you got to the PSI in the tires. If what you said was true then over all these years tire manufactures would have been improving tire casings to push the PSI limit ever so higher, we would probably have PSI's near 300 by now! And road surface has a lot to say about how much pressure one should be using. [FONT= 'Helvetica Neue']If it is chip sealed and you ride with a 19mm tire at 140psi, there is no question that you will have higher rolling resistance than with a 23mm pumped to 90psi (assuming that both are high quality high-thread-count tires). Every time you deflect the bike and rider up and back, it costs you energy, as opposed to absorbing the gravel hunks into your tire. This is the same reason that suspension makes a mountain bike, car or motorcycle faster on rough terrain. If you are riding on a smooth track, then use a 19mm tire and pump it up to super-high pressure. But even on smooth tracks you won't find pressures exceeding 170psi. Problem is that very few of us rides on a smooth track. Also your body weight plays a role in pressure. to find your ideal pressure, start in the middle of these ranges I'm going to give you then factor in your body weight, thus the more you weigh the higher the pressure needs to be. Example; aA 165 pound rider should use right around 100psi on the rear and 95 front. A 200 pound ride should run around 120 psi on the rear and 110 on the front, and a 130 pound rider with 80 in the rear and 75 on the front.[/FONT]
 

Thanks Froze, yes you are right it is dependant on road/track surface and the conditions of the day and even experience of the rider.
 
Some of the track guys do ride with 160 to 200psi (tubless tyres/singles/wooden surface), and the xc mtb guys ride with 50-70'ish, and the road guys with 90 to 120'ish [IMG]/img/vbsmilies/smilies/smile.gif[/IMG]

looks nice inf.

Thanks for the info guys.
 
As stated, I'm not looking for crazy ultimate performance, I'd have a lightweight road bike if that was the case (or a higher end FX more likely), I'm just looking to drop extra weight from the bike, and obviously the wheels are where the most improvement would happen. I guess the way I see it is I'm going to tinker with the bike regardless, so I'd like to tinker in the places where the gains would be the most profound... relatively speaking.
 
Personally, I don't like drop handlebars, I don't feel as comfortable, nor do I feel as in control as I do with the "mountain bike" posture the FX series has (one of the reasons I went with the FX). I'm considering changing the handlebars and stem to be more inline with the 7.9FX (7deg rise, flat bar) as a part of getting the fit more how I want it, so the lower posture might help with aero.
 
BTW, I dunno if "recreational" is the right word... I average at least about 110-120 miles per week and about 17mph over a 30 mile stretch. While I'm not racing/training in the strictest sense, I am out racing against myself, and competitive events might be in my future.
 
P.S. Tire pressures are a funny thing, as an ex autocrosser, tire pressures were one area where you could see profound gains, or huge problems if you got 'em wrong. I run my tires at ~100psi, the LBS had them at 60 when I got the bike. The 40psi difference certainly made a difference in rolling resistance, I noticed my average speeds go up.

Hi Joel,
 
Welcome to the forums and welcome to cycling. Looks like you are enjoying your bike and doing well, and that is what I always like to hear!!!!
 
I have the mavic aksiums. I agree with dhk when I say (speaking as a road racer) that they are nothing special. They are OK training wheels (not that I don't want better) but nothing to rave home about.
 
If you plan to get into racing and do mass start road races, you will need drop handlebars. Flat bar bikes can, however, be used for cyclocross. . . This isn't really anything you need to worry about now, but maybe in the future. However, on a well-fitted road bike, the drops should feel very comfortable/stable. Maybe the ones your tried just didn't fit well?
 
 
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Quoted post said:

Originally Posted by CalicoCat [IMG]/img/forum/go_quote.gif[/IMG]

If you plan to get into racing and do mass start road races, you will need drop handlebars. Flat bar bikes can, however, be used for cyclocross. . . This isn't really anything you need to worry about now, but maybe in the future. However, on a well-fitted road bike, the drops should feel very comfortable/stable. Maybe the ones your tried just didn't fit well?
 
 
 

That is entirely possible, I haven't ridden a drop bar bike in years because I hated it so much.
 
One thing I forgot to mention is the 7.3FX has an 8spd cassette, I'm seeing that many of the wheels upgrades out there are 9/10spd. Curious if I'm looking at a bigger project than just swapping out the wheels.
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Quote:[IMG]../../../img/forum/go_quote.gif[/IMG] Originally Posted by JoelS79  
One thing I forgot to mention is the 7.3FX has an 8spd cassette, I'm seeing that many of the wheels upgrades out there are 9/10spd. Curious if I'm looking at a bigger project than just swapping out the wheels.
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The guys I work with tell me that an 8-speed cassette will work with a 9-10-speed hub with a headset spacer, but I haven't tried it yet. Upgrading a 7.3 FX seems a little pointless to me, but lighter wheels are not terribly expensive, the mods are reversible, and you aren't going to break anything. So trying to get a little more kick by using lighter wheels falls under my classification of "why the hell not?"
 
Mavic Aksiums are considered training wheels, but even a training wheel will be lighter and more responsive than what you have, especially with skinnier tires. I recommend looking at other wheelsets in this range (2000 grams, $400) before settling on the Mavics. For tires, Continental GP4000s in 25mm ought to be fun.

Hi JoelS79
 
The following are some WheelSets that look good [IMG]/img/vbsmilies/smilies/smile.gif[/IMG]
 
Prolite Bracciano, Prolite Gavia Superlight (42mm), Easton EA90 SLX, Fulcrum Racing Zero, Campag Eurus 2 way fit
 
 
PS: For touring, I like flat bars also, especially when equipped with fast thumb indexed levers [IMG]/img/vbsmilies/smilies/smile.gif[/IMG]