impulsivo

Hi all,

I have a gravel bike (Bianchi Immpulso Allroad) to which I would like to fit some fenders. The issue that I have is that there is very little space between the tire and the chainstay bridge. Less than 1.5 cm, as you can see in the picture


The chainstay bridge has a bolt to hold the fender in place but, unlike most other bikes, this bolt goes vertically rather than horizontally. That is, it would hold the fender itself rather than a bracket holding the fender. I have tried fitting SKS Speedrocker fenders. They sort of fit, but I would need to drill a hole in the fender for the bolt. Not so much to hold the fender but rather to have a bit more space. In fact the hole should be slightly bigger than the bolt so that the part of the bridge where the bolt goes in and which is coming out (1-2 mm) would also go in there. It is not a great solution, but so far it is the best solution I have found.

I have tried having the fender go over the bridge. That is possible, but it looks horrible. I have also tried with SKS Bluemels (46mm, plastic). I can have that one fit, but it is not great either. It also looks quite cheap.

Does anyone have a good idea of a fender that could work with limited space between chainstay bridge and tire? In terms of width, there is room for a 46 mm wide fender, possibly even up to 50 mm. I have been checking a bit online and have not found anything relevant. Bianchi has fenders for this bike model, but they are sold out everywhere (I suspect they don't produce them anymore). I have the impression that this could be a fender produced by someone else and rebranded by Bianchi (I think it could even be SKS), but I have not been able to figure out more.

I have also searched for others with exactly the same bike (with fenders) I have only found one picture online of the same bike. It seems that some Bontrager NCS fender is used. They do not have it in any local shop here, but by chance I saw one bike having them at a store. It did not really look to me that these were going to fit very well, but it was hard to tell more without actually trying them.

I have not found anything interesting in local shops. They mostly have the two SKS models I mentioned above. Of course they also have these models that are attached to the seatpost, ass-savers, etc. I am not interested in having those. At least not yet.

Thanks!


/Impulsivo

PS: I had some pics to show all this, but I am new and cannot post them.

mpetry912 

This is an area that commonly demands a creative approach that is not satisfied by a SKU at the bike shop.

it sounds like you need to dig into your junk box ! The vertical hole is a challenge but not insurmountable. It may require that you fabricate an "L" bracket.

Here's one that I did on a Raleigh that needed a spacer. Style points are awarded for leather or rubber washers to eliminate noise and soak up vibration.

get creative ! you can do this.

/markp

79pmooney

I have no issues with trimming fenders for custom fit. My thought here - trim the sides of the fender so you have a central tab that runs forward of the chainstay bridge and the sides just touch the chainstays (A Dremel with a sandpaper drum would be the prefect tool for getting a nice tight fit.) Then make an "L" out of SS tang or the like to attach it the fender above the bridge and across the bridge for the vertical bolt. Drill fender and "L" and fasten with nut and bolt.

The bike of my avatar photo has an SKS fender I did just that to except the bridge bolt hole runs horizontal so no "L" needed. On that bike I use the entire 2" long horizontal dropout for the hub. (Fix gear that goes into the hills and uses cogs from 12 to 24 teeth, often on the same ride. With the 24t on, the wheel is very far forward and things are tight! Fender has a long, narrow elliptical hole to accommodate the seat tube. Framebuilder had to countersink the bridge hole to allow a flathead screw.

That was only the start of fitting that bike's fender. Next it got the cut and separate treatment ala RIver City Bicycles and other to go around the brake bridge. Finally the fender sides (flanges if you will) got cut in two places on each side, the fender straightened slightly at those locations, then fiberglassed inside to hold that new shape and keep it stiff. (To accommodate that 2" of hub slide.) And all done so taking the fender on or off takes 5 minutes.

It took me two tries to get it right. First fender worked but on and off was a real hassle and I did a much neater fiberglassing job and kept the overall shape straighter the second time around. Learning curve. Your challenge is far simpler and if you screw up, you can just trim a little of the front and try again. Just don't mention it is now 2" higher in back.

Edit: load your pictures to the BF album and tell us. Someone more savvy than me will post them.

Iride01 

Are these the pic's you wanted to put with this post...




There are more that can be seen in this album.... https://www.bikeforums.net/g/album/29453678

You might consider that the bike really wasn't made with the intention of mounting just any fender on it, if they even thought of someone wanting to mount a fender. Of course you can come up with something. Also consider with a tire that wide and the clearances to the frame and fender, if you were to ride through the sticky gumbo mud in my area that clings to the tire tread and sidewalls, you'd come to a very sudden stop.

impulsivo

Thanks to all for your replies

Iride01: those are the pics, thanks, I was not allowed to link them but I could upload them. Thanks again.

I don't plan to go through any mud, so I think clearance is otherwise good. Clearance on the sides looks worse in the pics than it actually is, even if it is certainly not for thick mud. That I was quite aware when I bought it.
It is possible that they never seriously thought about anyone using fenders (but they still sold them at some point!) or more likely the tire is a bit too big for what the frame as originally designed.

mpetry912: thanks for your insights. I don't mind having to do some hands work on this, but before that I thought it was a good idea to check with more knowledgeable people. If I were to do something, my current thinking is to drill a hole in the SKS speedrocker, but I would need to consider first if the structure would be too weak or not. I am also open to change my plan for a better one

79pmooney: thanks for the suggestion. I will try to find first a nice but thin (metallic?) fender. I am not sure a cheap plastic one would be suitable for that. That is at least my feeling after trying the SKS bluemels (which was what I could find at the local store)

dedhed

https://velo-orange.com/collections/fenders