Nashbar Reduced Radius Rollers

Nashbar Reduced Radius Rollers

Postby cure » Sun Dec 12, 2010 10:22 pm

Hi,

I will have this roller soon and was looking at the trainer list, went to rollers tab...whats strange about the rollers is that the diameter of drums is 85 mm...which is less than 3.5" but on the ibike software, only offers 3" drums...will this influence the power accuracy? do i have to do anything with the coefficients.

what does the power/ speed adjustment have to do with the roller settings? is this at a constant speed i must maintain?
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Re: Nashbar Reduced Radius Rollers

Postby NCH1 » Mon Dec 13, 2010 2:55 am

I have the latest version of the ibike software, and the coefficients (or speed/power curves) listed are for e-motion and Kreitler rollers. I would not use these settings for your rollers. On several occasions I have contacted the manufacturers directly and they have been more than happy to supply the speed/power curve when I explained that it was necessary for power training.

Unfortunately, I don't understand what the formula's for the coeffcients represent in the ibike software and have not found an explanation for them in the manual. On that note it would be nice if John or Travis could provide an explanation so that we can determine roller coefficients more specific to the individual rider, such as rider weight etc

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Re: Nashbar Reduced Radius Rollers

Postby Velocomp » Mon Dec 13, 2010 7:35 am

We'll have Travis post a response to your question.
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Re: Nashbar Reduced Radius Rollers

Postby travispape » Mon Dec 13, 2010 1:41 pm

As Nik mentioned, the rollers that we support are the models where the manufacturer has supplied formulas for calculating the resistance curve, which we don't have from Nashbar.

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Re: Nashbar Reduced Radius Rollers

Postby cure » Mon Dec 13, 2010 3:39 pm

thanks, but thats too bad...i'll have to find a way to ask them then...thank you.

the speed that can be manually chosen has nothing to do with user speed on bike...it only relates to the rollers right?
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Re: Nashbar Reduced Radius Rollers

Postby cure » Fri Aug 26, 2011 5:16 pm

sorry to bump this again...im wondering how else i could train on these rollers if my ibike wont work with these. can i measure through speed / heart rate? is there a good workout layout for rollers that wont work with the ibike? thank you.
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Re: Nashbar Reduced Radius Rollers

Postby travispape » Mon Aug 29, 2011 3:49 pm

Hi cure,

I've searched again, but still can't find any power curve data for these rollers. If Nashbar ever releases the data, we will be happy to include it our software.

But not all is lost. Fortunately, the resistance of the rollers is linear, unless the rollers have a pulley to drive a fan or flywheel accessory. As long as you don't have any such accessories, you can create your power curve based on your perceived effort. You will do the same effort on the road using the iBike to measure your power and you will do the same effort for the same time on the rollers. The results will be as accurate as your ability to put out the same effort both on the road and on the rollers.

1) Road test: Make sure your iBike is well calibrated--tilt cal and wind cal. Inflate the tires to your normal pressure. Warm up for at least 5 minutes (this gives the slope offset algorithm time to kick in if necessary). Do a max effort ride on the road for 20 minutes. This works best if you ride at a uniform power, so try to pick a long climb or a long flat if you have one available.
2) After you download the ride, make note of the AVG POWER for the 20 minutes. You can click-drag on the graph to select the 20 minute max-effort segment. The stats shown are for the highlighted selection.
3) Roller test: It does not have to be the same bike. Make sure the tires are at the correct pressure (115 psi for 700x23c). Tire pressure is critically important when riding on rollers because almost all of the resistance comes from the tires. Warm up and do another 20 minute effort at max effort.
4) When you ride on trainers or rollers you don't have the benefit of the headwind like on the road, so be sure to keep yourself cooled. Use a fan if you can. You don't want your effort to fall off because of getting too hot.
5) After you download the trainer ride, make note of the AVG SPEED for the 20 minute max effort on the rollers.
6) Creating power curve: Open the trainer window in the iBike SW: "Device -> Edit Trainer Settings..."
7) Click the "Coefficients" tab
8) Enter A = 0, B =10, C = 0, D = 0
9) Place the yellow cursor at the average speed for your TRAINER 20 min effort recorded in step #5. You can either drag the cursor into place your you can type the speed in the "@ Speed (mi/h)" number box shown in the raised box in the graph.
10) Tweak the value of B until you match the average power for your ROAD 20 min effort in step #2. Look at the "Power (W)" value in the raised box in the graph.
11) Once you have the match, click the "Save" button to save the results and click "Send to iBike" to send the coefficients to your unit.

NOTE: This procedure only works for "linear" trainers, such as rollers w/o accessories or mag trainers where all the resistance comes form the magnets and tires.

That should be it. You should now have a really good power curve for your rollers and can use the results for training.

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Re: Nashbar Reduced Radius Rollers

Postby cure » Fri Sep 02, 2011 9:51 am

travis,

thanks for the reply, i will try this out! i got the rollers and there are 3 rolls. on front for front wheel to sit on. and 2 in the back for rear wheel. there is a black rubber band that wraps around front and middle rolls, like a pulley action. will i have issues if its like that?
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Re: Nashbar Reduced Radius Rollers

Postby travispape » Tue Sep 06, 2011 8:50 am

cure wrote:travis,

thanks for the reply, i will try this out! i got the rollers and there are 3 rolls. on front for front wheel to sit on. and 2 in the back for rear wheel. there is a black rubber band that wraps around front and middle rolls, like a pulley action. will i have issues if its like that?


Nope, there should be no problems. With just the 3 drums, your power curve will be linear.

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Re: Nashbar Reduced Radius Rollers

Postby cure » Fri Sep 09, 2011 5:16 pm

thanks travis,

random question about the roller itself. Is it safe to ride out of the saddle if it’s a fixed roller, like it doesn’t move back and forth. I tried it once but didn’t want my back wheel to pop off or the front wheel slipping off front. The axles are all lined properly…I don’t want to go running in a wall 30 mph…:P is there a technique for this?
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Re: Nashbar Reduced Radius Rollers

Postby travispape » Mon Sep 12, 2011 1:48 pm

cure wrote:Is it safe to ride out of the saddle if it’s a fixed roller, like it doesn’t move back and forth.


I've never ridden rollers, but I did watch this video once: http://www.youtube.com/watch?v=wME5NTriTco :-)

Can anyone else help?
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Re: Nashbar Reduced Radius Rollers

Postby Todj » Mon Sep 12, 2011 6:35 pm

Used to ride roller racing leagues about 20 years ago. That was on track bikes, so I'd suggest that bike control was possibly a bit easier with fixed wheel. And yes, riding out of the saddle can be done, but you have to get your body lower, with fairly high leg speed and contol the front end to keep things straight.

One point to observe though is that, if you do come off the rollers at speed, then you'll not pile into the wall in front of you at 35mph. The tyres will simply spin out on whatever surface is underneath (and probably leave burn marks).

Here's another video clip:- http://www.youtube.com/watch?v=s-Shse9MT34
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