Rain & the Wind Port

[PAllen]

Although I've got a remote wind sensor (mainly for rides in the rain for me), I don't use it most of the time. With all the recent off and on rain in my area, I was wondering the effect on the iBike if the wind sensor was covered for a portion of a ride.

The scenario is that I start a ride not expecting rain (i.e without the RWR) but sometime in the ride there's a rain that's big enough to get into the wind port. What if I blocked the port? My expectations are that I'd still get speed, cadence, HR and % grade. I'm sure I wouldn't get accurate power or wind (or NP, TSS or IF). How about elevation and climbing? What would happen if the rain stops and the port is unblocked? What kind of errors in the ride data should I expect? Does the iBike default to an ordinary bike computer for this situation?

Thanks,

Paul

[pjboyle]

My experience with riding in the rain has been that the unit can tolerate a moderate amount of rain, but then eventually "drowns" if the intensity or duration reaches a certain point. The main way I can tell it has drowned is that the watts start to increase disproportionately to anything I'm actually doing on the bike. Later in ib3 the data shows a very high wind speed, which caused the high watts. I have done what you suggest and "blocked the port" (I tie a plastic bag over the entire unit), but I've never done it prior to the unit already giving the wacky wattages. I am mainly trying to prevent further saturation. While covered, I still get correct speed, distance, cadence, and HR. Wind and watts are obviously off. I don't think I was getting proper elevation because I also had the little hole on the underside of the unit inside the baggie (although doubtful it was airtight so odds are it would still read pressure variation). For the majority of my rides I am on nearly dead flat terrain so I can't vouch for the elevation reading. In one case after the rain stopped and I uncovered the unit, I was able to recover seemingly good data by shaking the unit out and remounting and it performed for the rest of the ride. On the other occasion it was too far gone and wouldn't recover a proper wind speed and the unit needed to be dried after the ride (open battery cover under a low wattage desk lamp). After the rides, I went into Excel and made estimated corrections to watts for the "bad" or covered sections, basically by comparing speed to the sections before or after, where the watts read correctly. This is of course facilitated by the ride being on flat terrain.

Why not carry the RWS with you and install it once it starts raining? This is what I've been doing lately. The only downside is in changing profiles to the RWS profile, it does a trip reset. If I am starting out in the rain or know it will rain during my ride, I've been taking a three-pronged tack and using the RWS for the whole ride, sealing the iBike/mount flange with two wraps of stretchy electrical tape, and covering the display area with a piece of clear packing tape. Using this approach the unit has survived 3 hr rides in steady rain as well as very heavy downpours.

PJBoyle

[lorduintah]

I think if you block the wind port, the iBike will interpret this almost entirely as a wind situation equal to the bike speed. So you will still get a power calculated, but without benefit of all the additional plus and minus power for aerodynamics. The altitude will still be sensed as will gradient or slope changes.

I am not entirely confident that the window is sealed, so you can still get water inside - this is why some are suggesting a strip of packing tape over the window to help reduce that likelihood.

Tom

[Morocco Mole]

My unit definitely isn't sealed properly around the Display, you can even see around the edges where the glass is lifting and water gets in pretty easy during rain. I can press the edges down flat again with my finger. Was curious if this is something I can reseal myself as I would rather not have to send the unit back in from Australia. As it is, it seems like I could lift the perspex cover out with a small knife under the edge that is lifting, and maybe re-installing with some silicon?

[lorduintah]

I was just looking at my iBike window. Some carefully applied silicone should provide a reasonable seal - maybe a q-tip or small paint brush (artist type not wall painter's) and you could get the goo into the crevice around the whole area. Might be that clear nail polish would do the trick, too - but I would let Velocomp have the final word on these choices to avoid deforming the plastic case.

Tom

[PAllen]

Thanks for the replies. I have a high stem angle so the water gets in the port rather quickly. I was planning on using the baggie trick this weekend. I'll post a reply on how it goes.

Paul

[Morocco Mole]

My unit definitely isn't sealed properly around the Display, you can even see around the edges where the glass is lifting and water gets in pretty easy during rain. I can press the edges down flat again with my finger. Was curious if this is something I can reseal myself as I would rather not have to send the unit back in from Australia. As it is, it seems like I could lift the perspex cover out with a small knife under the edge that is lifting, and maybe re-installing with some silicon?

Just an update, I didn't try re-sealing with Silicon etc but I have now placed a piece of Clear Contact (clear adhesive book covering) over the display. With some recent rain I can now confirm the unit is water resistant again . Interesting side effect is that my Wind Scaling has changed, most likely due to the better seal and therefore more accurate pressure reading by the sensor.

[rruff]

You covered the display and now the unit doesn't become saturated with water? I don't think I have any water getting in around the display, but I *do* have the water issue. Maybe there are multiple routes where it might get in? I also have a very high wind scaling (>3).

John (VC) mentioned once that the dynamic pressure sensor isn't referenced to static pressure or anything... but after thinking about it awhile, seems like it must be unless there is a vacuum that it references. Honestly, I don't know how it works, but if it just references the inside of the unit and the unit has gaps, then maybe you can get odd pressure variations inside it due to wind.

[Morocco Mole]

I'm not sure how the thing works, all I know is that the first time I got rain into the unit my wind scaling got screwed up (dropped from about .9 to .6) and has stayed that way ever since. I'm pretty sure CoachBoyd and other have made the same observation in the past. I then made my own RWS for wet weather riding and no longer get any water in through the front port, but it definitely used to get in under the display as my unit did not seem to be sealed correctly. I should send it back but I can't live without my iBike at the moment and my temporary fixes are working. Since sealing the display my wind scaling has gone back up to .907, maybe John can explain that?

[rruff]

I've noticed some variability in wind scaling as well, and can't figure it out. Have you checked to see if your wind offset drifts around? That might explain the variability of the wind scaling. Also, is your handlebar mounted unit right next to the stem, or farther outboard? If it's closer to your hands it might be affected in crosswinds.

Search for my name and "wind scaling" on this forum. It is very easy to check your wind scaling on any ride... and adjust it if necessary when you get home. At any rate it might be good to document exactly how much it varies and what the conditions are.

[pjboyle]

When you put the head unit in your pocket, it would be advisable to cover the mount. The mounted head unit provides some degree of protection to water intrusion to the mount. I carry a small plastic baggie and rubber band it over the mount while riding with not head unit (or when transporting the bike on a rack in the rain). Prior to these safeguards, I lost two mounts to internal corrosion. It rains once in a while in Louisiana so the topic is near and dear to my heart.

PJBoyle

[rruff]

Can you show us exactly how the contact paper is applied? I haven't noticed water intrusion at the screen, and it appears to be well sealed.

[rruff]

So you are just sealing the gap between the clear screen and the rest of the unit... yes? Maybe I should put a super tiny bead of silicone around all the interfaces...

[lorduintah]

Clear silicone tub caulk might be the ticket. There I would tend to use a small bead as the acetic acid in the silicone is pretty nasty to electronics. You might even get away with some paraffin wax or something similar...

Tom

[Morocco Mole]

The tip came from Morocco Mole, so maybe he would like to elaborate. I have not had evidence of water leakage past the screen, and after getting caught out in the rain, the battery compartment is bone dry. I tried the contact paper because Morocco Mole suggested that a tighter seal around the screen might help stabilize the air pressure differential. Perhaps the increased wind offset stability I believe I am seeing is due to this?

I applied the contact paper to an area just slightly larger than the border strip that surrounds the rectangular screen.

Hi guys, sorry have not had much time to respond as late. The Contact Clear I used was cut to size about 2mm larger that the plastic screen border, the stuff I used is slightly flexible so it was easy to press down and form around the curves of the iBike. I did think about using Silicon but decided to use something non-destructive that would not damage or modify the unit in anyway. I have spoken with tech support and I will be sending my iBike back in for proper resealing as soon as I get my hands on a loan powertap unit, although I will probably continue to use the contact anyway as a safeguard.

Have attached a pretty poor quality iPhone pic, you can hardly make out the contact covering, it's very unobtrusive.

Cheers
Jim

screen_pic.jpg (87.1 KiB) Viewed 17993 times

[travispape]

This would be a good thread to introduce a new feature that will be in the next release of the iBike SW. As was mentioned above, if enough water gets into the wind port, it can block the wind measurement and you can end up with a ride that looks like this.

before wind repair.png (197.21 KiB) Viewed 17913 times

With the next build, you can highlight the section of the ride that needs to be repaired and there is a new menu item under the Tools menu to repair it for wind in which case the wheel speed is substituted in for the wind speed. If you rode with a headwind or tailwind, you can enter the wind speed and it is added to (or subtracted from) the wheel speed. In the example below, I just did the default wind repair. Notice that it has an impact on power.

after wind repair.png (205.65 KiB) Viewed 17916 times

Travis

[rruff]

I was just thinking yesterday that it would be nice to be able to set a tailwind-headwind speed for different sections of a ride... this is because my wind offset varied between -4 and +5 and I can guess wind better than that. Since it varied so much though, setting an offset for the entire ride wouldn't work.

[lorduintah]

Travis -

Is this a once per ride repair or can multiple sections be addressed, one at a time - in the case of both sections of headwind and tailwind?

Tom

[travispape]

Travis -

Is this a once per ride repair or can multiple sections be addressed, one at a time - in the case of both sections of headwind and tailwind?

Tom

The latter.

[lorduintah]

Travis -

Thanks - I can see one more set of headaches for Coach and John arising from this affecting calibrations... but it is also the right thing to do - when stuff happens.

[wellmt]

That rain port example looks quite mild! Here is usually what happens for me once I turn the bike into driving rain. Great idea for a new feature though. I used the missing cadence function for the first time the other day, worked well.

For what it's worth though, I've never had any scaling issues or leakage around the display on any unit. I've always put a screen protector on the display but it doesn't really go right to the edges.

[Russ]

tommtyturbo,

Yes it happened to me after getting caught in a deluge! Once the iBike dried out, had to recalibrate. I think, in my case the net result was an improved (closer to 1) windscaling!

The permanent work around or fix is the remote wind sensor which, when riding in the rain, keeps the collected water down in the plastic hose (assuming you run it uphill to the iBike) and well away from the clog-gable parts. This also allows continued accurate wind scaling while in the rain. Another benefit is that you can more easily place the air input away from the turbulence caused by your hands on aero bars, etc, for a more consistent set of conditions (if I understand all the posts and descriptions I have read).

Being a wimp, I try to avoid the rain but may get a remote wind sensor for Christmas just incase and all.

Russ

[wellmt]

Does anyone know if you need to recalibrate at all when using an RWS or will your standard profile be good enough?

[coachboyd]

You will have to recalibrate when you get the RWS.
It's wise to have two profiles, one with the RWS and one without. This way if you need, you can switch it during the ride.