BigJeff

oh?

Traffic lights take 4-8 minutes to cycle, so hitting 2-3 fewer lights would increase your pace by 8-16 minutes.

so, it seems plausible that your speed increase was just two or three more green lights.

hueyhoolihan

i would need to duplicate that test 10-20 more times to even determine whether or not there is any difference at all. maybe more.

Carbonfiberboy 

All of the above. When I used to do long fast rides on my carbon single, I ran 23mm tires at 140#. Don't let anyone BS you. On smooth surfaces, high pressure is faster if you have a good frame. There's no question. 120# on 26mm tires would be be the same thing. On chip seal, depends on the size of the chips. Big chips, lower is faster. However, on a POS aluminum frame like my CAAD9, it's impossible to run hard tires.

And it's totally possible to save 20 watts by reducing friction, reducing crr, and reducing aero drag, all at the same time. The faster you're going and the flatter and smoother the course, the greater the reduction. TT bikes really are faster on the flat.

Inpd

I don't have a CF frame but would think the higher pressure tires can only improve speed but at the cost of comfort on well sealed roads.
@BigJeff, forgot to mention, I'm in the country areas, no 8 minute red lights. Often I just cycle,through the red lights or at worst slow down. But thanks anyway.

RJM

Taking a few days off probably helped and tires can make a big difference.

Carbonfiberboy 

Carbon can make a huge difference, but it depends on the frame. Some are quieter than others. What's comfort? Only made a difference to me if it slowed me down. Really sucked descending gravel Forest Service roads, and that's a fact.

StanSeven

By any chance are you riding in the drops more now with the lower stem?

RoadTire 

"The Roadbike Forum."

This place is like a gaggle of prepubescent girls, and a whole lot of ... fun. Most of the comments you received in this thread are entirely appropriate, as outlined in the Rules.
Velominati ? The Rules

I think Rule 10 applies to your situation.

Once I got in trouble for misinterpreting Rule 59 - Hold your line. I thought they meant the 6 foot wide black tarmac line between the pretty white lines on each side...

PepeM

Yes, me too.

BigJeff

post your route.

Stucky

Hate to spoil the fun...but did you input the new tire's size into your speedo?

If so...

I had the same thing happen to me last year, too- I just got on the bike one day, and was 1-2MPH faster for a few weeks...

Then returned to my normal tortoise pace.

Recently, for some reason, I've actually LOST .5-1.0 MPH -and ironically, I now have the best bike I've ever owned in my life. (In my case, I think the decrease in speed is due to my body being used to riding now, and thus my fitness stopped building and actually started regressing a little, since I haven't been increasing my distance or speed lately. In your case, it's probably the opposite: Your fitness is improving, and your reaping the benefits!!!!)

Andy Somnifac 

Yeah, and at my fittest I bordered on Cat2. Unfortunately my lack of tactics made sure I never got even close....

RoadTire 

Very good point. I calibrate my speedo by comparing it with the GPS on my rides. After a few rides, tweaking just a little, there is enough average speed data the sports can be tossed out and the rest tend to stay withing about 2%. I have no idea why I even think it's important, but that's just me.

Inpd

So I thought I addressed this earlier. I use MapMyRide so it uses GPS coordinates to measure speed and distance. Am I missing something with MapMyRide.

Stucky

GPS is often not very accurate when it comes to speed....and add in the possible inaccuracies of GPS in conjunction with a website, and..well..... (Someone on here in another thread recently posted one of these services- It may haver even been MapMyRide- not sure- hich listed a certain hill as being 5-something-percent grade! )

Do you have a simple bike computer? Just a cheapo Sigma or Cateye'll do it...where you input the actual diameter of your tire to the millimeter, and it counts the revolutions of a magnet on your spoke. They're more accurate than anything.

RoadTire 

Addendum: I missed the part using the GPS for speed - Stucky is right, that's pretty poor. Accurate distance on the bike computer and time = accurate speed.

If I could just measure the dia accurately... tried rollout, but was way off. Maybe using a cloth tapemeasure and get the circcumference to calc accurate dia?

Agreed: the GPS has a lot of sports in the data, so takes quite a few runs on the same route to get some reliable coorolation. But hey, it was fun to see if I could do it. I didn't have anywhere I could ride back and forth using mileposts to get a good average.